Upon moving to New Mexico after winter vacation ends, Gabriella is surprised to find that the school she has just transferred to, East High School, is the same school Troy attends. In an attempt to confirm her identity, Troy calls her phone during homeroom, getting them both detention but verifying that the girl he thought he recognized is actually her. They continue their friendship at East High despite being in different social circles (Troy is a jock and Gabriella has been adopted by the school's brainiacs). Troy shows Gabriella around the school, and they notice the sign-up sheet for the school musical. Thanks to their previous singing experience at the New Year's Eve Party, they both internally debate auditioning.
They sneak into the auditions later and are surprised to see each other there. They remain together in hiding while Ryan and Sharpay, the school's brother-and-sister team of drama royalty, audition. Rather suddenly, Gabriella emerges from her hiding spot and asks to audition, and Troy abruptly jumps up and volunteers to be her partner. After being told that they are too late, they help Kelsi, the pianist, pick up her things. She plays them the song What I've Been Looking For (Reprise), which Troy and Gabriella then sing together. Ms. Darbus, the theatre teacher, hears them singing, and gives them a callback audition. Once everybody in school learns that they are singing together, both Troy and Gabriella receive pressure from their friends to forget about singing.
When Sharpay discovers that Troy, a jock (who's her crush), and Gabriella, a nerd, have a shot at being leads in the school play, she is enraged, and attempts to rally the student body around the idea that no one should do anything outside the realm of his or her clique. After the rest of the school find out about Troy and Gabriella auditioning, people start admitting secret hobbies and breaking the status quo. This causes all the students in the cafeteria to start sing Stick to the Status Quo. Troy leaves a note in Gabriella's locker, so she will meet up with him on the rooftop. On the rooftop, Troy and Gabriella talk and Gabriella tells Troy that sing with him felt "just like kindergarten".
Troy and Gabriella decide to do the callback despite the resistance they are facing, so their friends resort to tricking them out of it so they are more focused on "important things", such as the 'big game' and the scholastic decathlon. Gabriella is called into the science room to watch a video of an unknowningly filmed Troy lying to his friends about how the callbacks aren't important to him. Upon hearing this, Gabriella is devastated and comes to the conclusion that things between she and Troy were never meant to work out. She then sings When There Was Me and You, in which Gabriella indicates she has feelings for Troy that run deeper than friendship. Completely crushed, Gabriella tells Troy that they won't be doing the callback. She is obviously upset, something even her friends notice, and acts very withdrawn, totally unaware that Troy is acting the same way.
Eventually, Chad and Taylor (the ringleaders of Troy and Gabriella's respective cliques) realize their mistake has made their friends extremely unhappy and eventually tell them both the truth. Taylor hints at Gabriella's feelings for Troy, saying that what really matters is how she feels about her friends "and even more... Troy." Unfortunately, Gabriella is too hurt to believe them and continues to avoid Troy. Chad, Zeke, and Jason find Troy on the rooftop garden and tell him that they know why Gabriella won't speak to him, prompting him to go apologize for what he said. However, when he arrives at her house to apologize, Gabriella asks her mom to tell him that she's busy with "homework and such." In a desperate attempt to win her over, Troy calls her and Gabriella listens as he explains what happened. He climbs onto her balcony with their sheet music, and after he sings Start of Something New (Reprise) to her, she forgives him. The two seem to become closer than ever after this.
At school, Troy and Gabriella discover that the callback dates have been changed by Sharpay and Ryan to overlap with both the basketball game and the scholastic decathlon, meaning that they would have to chose which event to attend -- sing together or compete with their respective teams. After setting off odorous chemicals and messing with the lighting in the gym, Troy and Gabriella find a way to do all three events. However, stage fright returns to Gabriella as the whole school files into the auditorium to watch her auditon with Troy, who is able to break through her shyness by reminding her that it was "just like kindergarten" and to just "look right at him." After singing Breaking Free, Troy presses a kiss to Gabriella's cheek and she giggles, blushing. Troy and Gabriella end up winning the callback.
What Time Is It? (Summer Time). Troy and Gabriella meet up at Gabriella's locker and Troy gives Gabriella a 'T' (which stands for Troy) necklace. Troy and Gabriella then almost kiss, but are interrupted by a student who wants Troy to sign his yearbook. Troy promises to teach her how to skateboard, and Gabriella giggles that she has first aid training to patch herself up afterwards. However, their plans change slightly when Troy is offered a job at Lava Springs (courtesy of Sharpay's scheming) and brings Gabriella along to lifeguard. The rest of the Wildcats work in the kitchen.
Later on, the Wildcats win the basketball championship game and Gabriella's team wins the scholastic decathlon. Troy nearly gets a kiss from Gabriella, only to be interrupted by Chad and then, moments later, Taylor. Everyone then starts to dance and sing We're All In This Together. The movie ends with the pair on more than friendly terms.
Troy and Gabriella go on a picnic on the golf course, playing around and nearly sharing a kiss before being interrupted by sprinklers that were activated by a spying Sharpay. They also sing a song that Kelsi has written You Are the Music in Me with hopes of them entering the country club's Star Dazzle talent show. As time goes on, Sharpay develops her plan to pull Troy away from Gabriella—and his friends—by promoting him to a golf job where she takes lessons and monopolizing his time. She also manages to trick him into promising to sing with her You Are the Music In Me (Sharpay Version). Gabriella becomes slightly jealous and Taylor begins insisting that Troy is behaving inappropriately according to her (Taylor's) sister's "boyfriend rules".
As times goes on, Troy begins to spend more time with Sharpay, coming late to, or even skipping, dates with Gabriella. Once Troy begins ignoring his friends and Sharpay, in her plans grand finale, bans all working Wildcats -- not including 'honorary member' Troy -- from the talent show, Gabriella tells Sharpay that she has had enough. Gabriella sings Gotta Go My Own Way to Troy. Gabriella gives Troy back the T-necklace that he gave her. She leaves Lava Springs, breaking up with Troy and leaving him stunned and brokenhearted . With absence, his friends' indifference towards him becomes glaringly obvious and he realizes that he need to make some changes. He tells off Sharpay and returns to his old kitchen job, attempting to win forgiveness from his friends. However, Gabriella is still out of the picture.
The night of the Star Dazzle talent show, Troy agrees to sing with Sharpay if she will let the Wildcats do the show. Depressed, Sharpay tells him that she wishes he was doing this for her and not for his friends. He only smiles sadly, knowing that he's dedicated to Gabriella. His friends drag him away to teach him the new song that Sharpay wants to sing. An uncomfortable Troy goes up on stage alone, waiting for Sharpay to come sing with him. However, Sharpay doesn't know the song he was just taught and cannot go join him to sing. Troy starts to sing Everyday and then hears Gabriella's voice accompanying him, and learns that Taylor had gone to get her from home, returning the T-necklace he gave her to its proper place around her neck.
She forgives him for everything that has happened and the two realize that they should be seizing the day. Later, all the Wildcats go to watch the fireworks on the golf course and, as their friends dance around in the sprinklers, Troy and Gabriella share their first kiss, boyfriend and girlfriend once again.
Towards the end of their senior year, Troy and Gabriella are still dating and are very serious about their relationship. During the championship game against West High, Troy looks to Gabriella for support and she encourages him to keep trying and, ultimately, to win. This all happens while they sing Now Or Never. Later, at the celebration at Troy's house, Gabriella and Troy hang out in his tree house and discuss their futures, namely the fact that Gabriella has already been accepted by Stanford University while Troy is being pushed towards U of A, two schools that are 1,053 miles from each other. Both teens are clearly uncomfortable with the idea of such a long distance separating them, and decide to focus on the present for the moment. They then sing Right Here, Right Now.
The Wildcats are later recruited to help with the school musical, Senior Year, and Gabriella mentions the idea of staging the perfect prom. Later, on the rooftop, Troy asks her to go to prom with him, both teens admitting that it is the first time they will be attending a dance together or alone, and Gabriella teaches him how to waltz while they sing Can I Have This Dance? They nearly share a kiss in the rain but are interrupted by the school bell ringing. Their relationship develops as they practice for the musical by singing A Night To Remember and Just Want To Be With You, and one day after rehearsal Troy takes Gabriella home, and while they sit in her backyard, she chides him that he should be able to tell his dad and Chad that he actually enjoys performing. He replies that while she and her mom both chose Stanford as the place she should be, he feels that University of Albuquerque was chosen for him not by him, and admits that he's been talking to schools other than U of A. Gabriella also admits that she has some decisions left to make, but her mother cuts her off before she can tell Troy what she means.Gabriella learns that she has been accepted into Stanford's 'Freshmen Honors Program' and would be leaving two weeks early, missing prom, the show, and graduation. Taylor encourages her to go, but Gabriella claims that she has been considering staying in Albuquerque, obviously in order to stay closer to Troy at U of A. When Troy learns about this, from a sneaky Sharpay, he sneaks into her room with a picnic and insists that she should go because she "can't put off something as great as Stanford." Although Troy's insistence does ultimately convince her to go, she finds that it is too hard for her to say goodbye and leaves without a word, planning to return for prom, the show, and graduation.
After two weeks apart, Gabriella makes a phone call to Troy and tells him that she won't be coming back because she can't handle having to say goodbye to her friends and, more importantly, him, again. She admits that she loves him (the first time it's said by either of them), but hangs up without giving him a chance to reply. She is later surprised when Troy shows up at Stanford on the night of prom back in Albuquerque. He explains that "if [he's] going to have a last dance at East High, it's going to be with [her]" and manages to convince her to come back to East High with him for the show and graduation by singing Can I Have This Dance? (Reprise). At the end of 'Senior Year', Troy reveals that he's made the decision to attend UC Berkeley to study both basketball and theater, a school that is only 32.7 miles away from "the person who inspires his heart." Gabriella is extremely touched by this, and, after graduating, the two head off to college, still together.
Troy: But seriously, you have an amazing voice. You're a singer, right?
Gabriella: Just church choir is all. I tried to a solo and nearly fainted.
Troy: Really? Why's that?
Gabriella: I took one look at all the people staring at me and next thing I knew I was staring at the ceiling. End of solo career.
Troy: Well with the way you sang tonight, that's pretty hard to believe.
Gabriella: Well that was the first time I've done something like that. I mean, it was so cool!
Troy: I know! Completely!
Gabriella: Well you sounded like you've done alot singing, too.
Troy: Yeah sure. My shower had its variables.
Gabriella: I guess I better go find my mom and wish her a happy new year.
Troy: Yeah, me too. I mean, not your mom. My mom... and dad. Uh... I'll call you. I'll call you tomorrow.
Troy: Here, put your number in.
(They take out their cell phones)
(Troy takes a picture of Gabriella)
Gabriella: You too.
(Troy takes a picture of himself with Gabriella's phone)
Troy: There you go.
(Gabriella walks away without Troy noticing)
Troy: Just so you know, singing with you is the most fun I've had on this entire vacation. So um... where do you live?
(Troy discovers that Gabriella has left. He looks at the picture of her in his phone longingly)
Gabriella: I don't...
Troy: Believe it.
Gabriella: Well me...
Troy: Either. But how?
Gabriella: Well my mom's company transferred her here to Albuquerque.I can't believe you live here. I looked for you at the lodge on New Years Day.
Troy: (whispering) I know, but we had to leave first thing.
Gabriella: Why are you whispering?
Troy: What? Oh, uh... well my friends know about the snowboarding. Um, I haven't quite told them about the singing thing.
Student: (to Troy) Hey, what's up?
Gabriella: Too much for them to handle?
Troy: No, it was cool. But, you know, my friends, it's uh... it's not what I do. That was, like,a different person.
(Gabriella suddenly turns and goes down a hallway as Troy finishes his sentence)
Troy: So, uh... anyway, welcome to East High. Oh, now that you've met Miss Darbus, I bet you just can't wait to sign up for that.
(Troy points at the winter musical sign-up sheet tacked on the bulletin board)
Gabriella: I won' be signing up for anything for awhile. I just wanna get to know the school. But if you sign up, I'd consider coming to the show.
Troy: Yeah, yeah. That's completey impossible.
(Gabriella comes up behind Troy and startles him)
Gabriella: Hey! So you decided to sign up for something?
Troy: Uh... No. You?
Gabriella: No. Um... why are you hiding behind a mop? Your friends don't know you're here, right?
(Kelsi plays the intro to the song, but the sixth singer is overcome with stage fright and just freezes)
Miss Darbus: Thank you. Next.
(The sixth singer runs off the stage in shame)
Troy: Um... Miss Darbus is a little... harsh.
Gabriella: The Wildcat superstar's afraid?
Troy: No! No, I'm not afraid, I... I'm just... scared.
Gabriella: Me too... usually.
Gabriella: I'd like to audition, Miss Darbus.
(Troy stands in shock over what Gabriella just did)
Miss Darbus: Timeliness means something in the world of theater, young lady. The individual auditions are long, long over and there are simply no other pairs.
Troy: (from his hiding spot) I'll sing with her.
Miss Darbus: Troy Bolton? Where is your sports posse or whatever it's called?
Miss Darbus: Ah.
Troy: Um, but I'm here alone. Actually I came to sing with her.
Miss Darbus: Yes, well, we take these shows very seriously here at East High. I called for the pairs audition, and you didn't respond. Free period is now over.
Troy: (about Gabriella) She has an amazing voice.
Miss Darbus: Perhaps the next musicale.
(Gabriella opens her locker allowing a note to fall. She picks up the note and reads it. A smile appears on her face as the scene changes)
SCIENCE CLUB ROOF
(We find that it was Troy who left the note in Gabriella's locker, and that he is waiting for her. Gabriella arrives)
Gabriella: Wow! It's like a jungle up here.
Troy: Yeah, just like that cafeteria.
Gabriella: Where I just humiliated myself into the next century.
Troy: No! Come on.
Gabriella: So this is your private hideout?
Troy: Yeah. Thanks to the science club. Which means that my buddies don't even know it exists.
Gabriella: You pretty much have the school wired, don't you Troy? Seems to me like everyone on campus wants to be your friend.
Troy: Unless we lose.
Gabriella: I'm sure it's tricky being the coach's son.
Troy: Makes me practice a little harder, I guess. I don't know what he's gonna say when he finds out about the singing.
Gabriella: You worried?
Troy: My parents friends are always saying, "Your son's the basketball guy. You must be so proud." Sometimes I don't wanna be the "basketball guy." I just wanna be a guy. You know?
Gabriella: I saw the way you treated Kelsi at the audition yesterday. Do your friends know that guy?
Troy: To them, I'm the playmaker dude.
Gabriella: Then they don't know enough about you, Troy. At my other schools I was the freaky math girl. It's cool coming here and being anyone I wanna be. When I was singing with you I just felt like... a girl.
Troy: You even look like one, too.
(Gabriella giggles softly at Troy's joke)
Gabriella: Do you remember in kindergarten how you'd meet a kid and know nothing about them, then ten seconds later you're playing like you're best friends because you didn't have to be anything but yourself.
Gabriella: Singing with you felt like that.
Troy: Well, um... I never thought about singing. That's for sure. Till you.
Gabriella: So you really wanna do the callbacks?
Troy: Hey, just call me me freaky callback boy.
Gabriella: (giggling) You're a cool guy, Troy. But not for the reasons your friends think. And thanks for showing me your top-secret hiding place. Like kindergarten.
(Bell rings. Troy and Gabriella both sigh as Troy takes Gabriella's hand as they get back inside)
Gabriella: Wow. So this is your real stage.
Troy: (chuckles) Yeah. I guess you could call it that. Or just a smelly gym.
(Troy hands the ball to Gabriella who shoots the ball and makes the basket, impressing Troy)
Troy: Whoa! Don't tell me your good at hoops, too.
Gabriella: You know, I once scored 41 points on a league championship game.
Troy: No way.
Gabriella: Mm-hm. Yeah, and in the same day, I invented the space shuttle and microwave popcorn.
Troy: Oh! Microwave popcorn. Ha-ha. Funny.
(Troy shoots the ball and makes another great basket)
Gabriella: I've been rehearsing with Kelsi.
Troy: Me, too. And, um, by the way, I missed practice. So if I get kicked off the team it should be on your conscience.
Gabriella: (getting a bit defensive) Hey, I wasn't the one who told you to sing...
Troy: (becoming playful) Gabriella, chill.
(Gabriella decides to take the ball from Troy)
Troy: (as Gabriella takes the ball away) Hey, that's traveling. (door opens) No that's really bad traveling.
Gabriella: What? What?
(Troy runs up behind Gabriella and picks her up and spins making her laugh as the door that opened closes)
Coach Bolton: Miss! I'm sorry, this is a closed practice.
Troy: (taken aback by his father) Dad, come on, practice is over.
Coach Bolton: Not till the last player leaves the gym. Team rule.
Gabriella: Oh, I'm sorry, sir.
Troy: Um, Dad, this is Gabriella Montez.
Coach Bolton: (rudely) Ah, your detention buddy.
(Gabriella's warm smile fades as she hands the ball back to Troy)
Gabriella: I'll see you later, Troy. Nice meeting you, Coach Bolton.
(Gabriella runs out of the gym)
Coach Bolton: (calling after her in a montone voice) You as well, Miss Montez.
Troy: Hey, how you doin'? (Gabriella is silent) Listen, there's something I wanna talk to you about,
Gabriella: (turning to face Troy) And here it is: I know what it's like to carry a load with your friends. I get it. You've got your boys, Troy. It's OK. So we're good.
Troy: Good about what? I was gonna talk to you about the final callbacks.
Gabriella: I don't wanna do the callbacks either. Who are we trying to kid? You've got your team and now I've got mine. I'll do the scholastic decathlon and you'll win the championships. It's where we belong. (She reaches into her locker and hands Troy her copy of Breaking Free) Go, Wildcats.
Troy: But I...
Gabriella: Me neither. (Gabriella walks away)
(Troy is about to go home when he gets an idea. He silently goes around to the back of Gabriella's house and dials her number on his cell phone. Gabriella is sitting on her bed when her phone starts ringing. She picks up)
Troy: (on the phone) What you heard, none of that is true. I was sick of my friends riding me about singing with you, so I said things I knew would shut them up. I didn't mean any of it.
(Gabriella turns on her nightstand lamp)
Gabriella: (on the phone) You sounded pretty convincing to me.
Troy: (on the phone) Listen, the guy you met on vacation is way more me than the guy who said those stupid things.
Gabriella: (on the phone) Troy, the whole singing thing is making the school whack. You said so yourself. Everyone's treating you differently because of it.
Troy: (on the phone) Maybe because I don't wanna only be the basketball guy. They can't handle it. That's not my problem, it's theirs.
Gabriella: (on the phone) What about your dad?
Troy: (on the phone) And it's not about my dad. This is about how I feel, and I'm not letting the team down. They let me down. So I'm gonna sing. What about you?
Gabriella: (on the phone) I don't know, Troy.
Troy: (on the phone) Well, you need to say yes. Because I brought you something.
Gabriella: (on the phone) What do you mean?
Troy: (on the phone) Turn around.
(Gabriella turns around and sure enough, Troy is standing on her balcony. They hang up their phones as Gabriella goes to the door and opens it)
Troy: (singing in acapella)
This could be the start of something new
It feels so right to be here with you
looking in your eyes
I feel in my heart
The start of something... (spoken) new.
(holds up Gabriella's copy of Breaking Free)
Troy: It's a pairs audition.
(Gabriella has made her choice. She walks over to Troy with a smile and takes the music sheets.)
(Troy coming down a hallway. He stops, checks an invisible watch on his wrist, just as Gabriella comes up and takes his hand)
Troy: Whoa! (They take off in the direction that Troy came from) You're late!
(Troy hands Gabriella a microphone. Troy nods to Kelsi who begins playing the intro to Breaking Free. However Gabriella is frozen. Troy sees this and motions for Kelsi to stop.)
Gabriella: (to Troy) I can't do it, Troy, not with all those people staring at me.
(Gabriella tries to walk away but Troy grabs her arm)
Troy: (softly) Hey, hey, look at me, look at me, right at me. Right at me. It'll be like the first time we sang together. Remember? Like kindergarten.
(Gabriella, now in a red dress, runs up to Troy and hugs him from behind)
Gabriella: (happily) Congratulations, Wildcat!
Troy: (excitedly) What about your team?
Gabriella: We won too!
(Troy moves in to kiss Gabriella, but Chad ruins it)