NOTE: This first time spoiler was sent in by Kalina.
Step Up 2 starts out with Andie (Briana Evigan) narrating about how The Streets started and how her mom encouraged her until her death. It then cuts to a subway station.
The train pulls in and some random people get on and off. A homeless man gets onto the subway hunched over with a blanket over his back and he looks very suspicious. An older gentleman is watching him and becomes shocked when he sees the homeless man turn around with a mask on his face. The homeless man pulls out a pair of drumsticks and he starts banging on the door. Then you see another man with a mask on and he is jumping around and doing flips he starts to mess with a nurse and a girl. Next thing you know they have masks on to and they all start dancing and doing flips and such. A security officer tries to get into the subway car they are in but the door is jammed. As the train stops, they all jump off and are being chased by the cops. They do a few more tricks in the subway station and this businessman points out where they went. They all run out of the station and you see the businessman going up the escalator with paint on his hand. The camera pans out to see graffiti on the wall for the 410. The girls are all running and throw the masks in the dumpster and they 410 crew all meets at the top of this building. You then see Tuck (Black Thomas), the leader of the crew, talking to Andie and asking her if she is coming over tonight. She says she is going to try and goes home.
Andie walks into her home where her guardian, Sara is watching the news about what happened on the subway. She tells her son to go upstairs and her and Andie get into a fight. She tells Andie that she is tired of her skipping school and running around with the 410. She is going to send her to her Aunt's in Texas. Andie freaks out and sneaks out of the house. She calls one of her girls and says she needs a place to stay and that she is heading to the Dragon (night club). She goes to the Dragon and she bumps into Tyler Gage (Channing Tatum). He tells her that he stopped by to see her and that Sara told him she ran away. He offers her another option, by going to MSA where he went. She says no and he challenges her. If he wins she goes if she does then he never saw her. The DJ clears the dance floor and they start dancing. There is a guy in a black hoodie watching from the crowd. Tyler does a really cool move and wins the challenge. She grabs her stuff and bumps into the guy in the hoodie. He tells her they are just jealous cause her dancing is off the hook. Tyler confronts her about leaving. She tells him no that she is not running and they go home to convince Sara. Sara and Tyler argue a bit and then he tells her she has her shot. She tells him Thank you for getting her in and he says, " I got you an audition. Now all you have to do is get in.
The next morning you see her standing outside MSA with her girls, Missy (Danielle Polanco) and Felicia (Telisha Shaw). They wish her good luck and she goes into the school. It then cuts to the auditorium where the panel of judges is watching a girl doing ballet. Chase (Robert Hoffman) makes a comment that its boring and Director Collins (Will Kemp), who also happens to be Chase's big brother, comments on how all the judges agree that its technique that makes you a dancer. Next Andie walks in and she hands her ipod to Chase, he gives her a smile and walks over to the stage. The music starts and she starts dancing. She goes for about a minute or so and the music cuts off. She rolls her eyes and leaves. Chase challenges his brother by saying, " I thought you said you could turn anyone into a professional."
Andie is at practice telling Missy and Felicia about how she screwed up at her audition and her phone rings. Tuck gets mad and she walks away to take the call. She runs back and tells Missy and Felicia she got in. Tuck makes an announcement that they need to be more serious and how the 410 are a family. He says they have to be to practice on time no exceptions and no cell phones and looks at Andie.
Andie shows up at MSA the next day and she is looking around. It then cuts to her at lunchtime. She is going to an empty table that is near the trash. She is sitting there and this guy walks about and says she is in his seat. He then goes to the other side and introduces himself as Moose (Adam Sevani). He shows her some handshake and starts talking about the school and how he knows everything going on. He is showing her around and she sneaks off and runs into Chase. He tells her he is glad she got in and that she is an amazing little dancer. She confronts him on the little part. Moose then comes up and she says they have to go do something, to which Moose doesn't get the hint and she walks off with him a little embarrassed. We then see Andie in Dir Collins class. He tells everyone they are going to do a little improv. As the first guy is going Chase walks in late. Dir Collins makes a comment and Chase calls out his brother. Dir Collins then says Chase is next. He does his improv and everyone is impressed except his brother. Dir Collins then calls on Andie. He puts on slow music and she asks him if he is serious. He tells her to listen and interpret the music. She starts dancing her way and then he stops her and tells her to try again. She listens and starts dancing her way but in slow motion. She then starts shaking her but slow. Dir Collins pulls her aside and says she needs to take this serious and that she is behind and now has to come to lessons with him after school. She tells him she can't but he doesn't listen.
We then see her going through practice with Dir Collins and Felicia covering for her when she is late or does not show for rehearsal with the 410. Her and Moose are talking and his phone starts ringing and he freestyles for her. They bump into Chase and he is kind of mean to her. She finally misses an entire rehearsal and gets a ride from Chase, after he apologizes to, her to practice. Tuck confronts her and Felicia refuses to cover for her. Tuck finds out she is attending MSA and kicks her out of the crew. They all walk away and you see Missy feeling bad for Andie.
Andie goes to school the next day and Chase asks her what’s wrong. She tells him that she got kicked out of her crew. He tells her to start her own and she says no and who would be in it. He tells her that he would and he goes through a few outsider students and the school. She also includes Moose. They all start practicing at the school after hours. They decide to go check out the competition at the Dragon. They are challenged by Tuck. They don't do well and are shown up by the 410. The next morning they are all sulking and Missy comes in to tell Andie that she thinks they did her wrong and that she has quit the 410. She is then volunteered by Andie to help. Missy asks them about the prank they are going to do. Chase says he has an idea.
Tuck comes into his house and asks why it smells rank. They blame it on one of the guys. A member of the crew tells Tuck he needs to see this and he walks over to the computer. They proceed to watch a video of them dancing behind Tuck at different places. They then show them dancing in Tuck's place and they hide a fish in the air vent at Tuck's place. It ends saying the MSA Crew are the new fish in town. Tuck then gets pissed and flips the computer over.
The MSA Crew are leaving the school and we see Sophie (Cassie Ventura) coming up to the school to practice for the benefit. She then invites herself to Missy's family barbeque with the rest of the group. They all go over and Missy takes Andie upstairs to get her ready. Missy then introduces Andie to her cousin who asks Andie to dance. Chase sees Andie all dressed up and is very attracted to her. He is watching her when Missy's aunt asks him to dance. He is dancing when he switches partners and steals Andie. They are dancing and Cassie gets up to dance to try and make Chase notice her. She switches partners to Moose. Andie and Chase are dancing and really getting into it when Missy pulls Andie away. One of the 410 is watching and texts Tuck about what he sees. Later they are cleaning up and Andie asks Chase to help her up in the tree with the lights. They are talking and Moose and Sophie have hit it off on the ground. Andie tells Chase about how she feels since her mom died of cancer. They are about to kiss when a truck pulls away and shines his headlights on them. Sophie and Moose see them up in the tree.
Chase is leaving the party to go home and Tuck and two other members of the 410 stop him. They tell him to stay away from The Streets and further away from Andie. They then beat him up and leave him on the street. The next day at school Andie goes up to Chase and sees that he is hurt. He tells her its nothing and walks off. There is a commotion in the dance studio and as they walk in they see that the 410 have trashed it. Dir Collins is upset and yells for them to clean it up. Andie goes to talk to the MSA Crew and tells them she is sorry for getting them in trouble and that it’s over. She is then called into talk to Dir Collins. He tells her he is disappointed and asks who else is involved. She says no one else and he expels her. She is leaving when she runs into Chase. She tells him its done and leaves. As she is walking home. Sara sees her and tells her she is going to Texas. Chase tells his brother that he was involved and that the crew was his idea. Dir Collins refuses to change his mind on his decision with Andie. Andie refuses to take Chase's calls. She is packing when she gets the text as to where The Streets are going to be that night. Chase and the MSA Crew are at the school benefit and they get the text. Chase walks out and the crew starts to follow. They all go to Andie's house to get her to go. Sara over hears them telling her that they know she took the blame for them and that Andie has helped them out. Sara tells Andie that she is proud of her and that she should go. Andie and the crew head to The Streets.
At the benefit Dir Collins asks Sophie where they are. She tells them they are at The Streets. He says he is going. Moose says he is part of the crew and that he will take them there. Sophie tags along. At the Streets you see different groups dancing. The 410 see Andie there. Felicia confronts her and they all start getting into a fight. The DJ tells them to back off and then the 410 dance. They refuse to let the MSA Crew dance. Andie gets up by the DJ and Chase has him stop playing. Andie gives a speech about how the Streets are about bring something new to the floor no matter where you are from. Then she challenges the 410 by saying " If the 410 are too scared to the defend their title. Then her crew will be outside where the streets started doing their thing. Dir Collins sees her speech and follows the crowd outside. The only ones not leaving are the 410. The DJ starts the music as it starts raining and the MSA crew start their dance with flashlights on their hands. They proceed to do an amazing dance as it rains harder. Everyone is cheering and they end up having the best dance.
Andie walks up to Dir Collins at the end and he says he is proud and that she is to be in his class on Monday. He also tells Moose that he is in the wrong program and will be dancing now in school. Sophie tells Moose that she likes their dance and kisses him. He is stunned and then goes after her. Chase and Andie go toward each other and comment each other on dancing and forming the crew. They end with a kiss.
During the credits they show more dancing.