Act One

The lights come up on an amateur boxing club in a Philadelphia church basement in 1975. Rocky Balboa, a fighter, is in the ring with Spider Rico. Rocky has the crowd enthralled as they cheer him on ("Ain't Down Yet"). Rocky takes the money he's won from the match, determined to prove his worth as a boxer.

Heavyweight champion Apollo Creed arrives in Philadelphia for a major fight. Meanwhile Adrian Pennino is getting ready to close up the pet shop she works at. Her coworkers Gloria and Joanne tell her she needs a makeover and to let herself have some fun ("Holiday"). Rocky enters the store and tries to make conversation Adrian. He asks her out, but she declines. He leaves, and Adrian watches him while thinking about how her upbringing has forced her to retreat into herself ("Raining").

Rocky works for Mr. Gazzo, demanding money from men who owe him. This time, he has to approach Wysocki, a butcher. Wysocki begs for mercy and Rocky, out of pity, makes him promise to have the money the following week. Rocky goes to Mickey's Gym where he trains, only to find his locker has been given to a new fighter, Dipper Riley. When Rocky asks Mickey why, Mickey tells Rocky that he's not a serious enough boxer and should move on to something else.

Apollo Creed's big match is about to fall through when his opponent drops out due to an injury. Apollo and his team look for a local boxer to take the spot. Rocky, going by the name "The Italian Stallion", catches their eye. Apollo sees this match as perfect timing for America's bicentennial ("Patriotic").

At Adrian's house on Thanksgiving, her brother Paulie explains to Gloria that he's set up Adrian to go on a date with Rocky so he'll put in a good word with Gazzo for him. Adrian does not know about this date. When Rocky shows up and Paulie announces that she's going on a date with him, Adrian is horrified and runs to her room. This escalates into a vicious fight, ending with Paulie throwing her turkey out the window. Rocky calmly asks Adrian to give him a chance ("My Nose Ain't Broken"). Adrian agrees to go out with him.

Rocky takes Adrian to a skating rink. It's closed, but he manages to convince the rink's watchman to give them ten minutes. As Adrian skates, Rocky tells her that because they're opposites, they go well together ("The Flip Side"). Adrian begins to open up to him.

Adrian reluctantly goes back to Rocky's apartment. When Rocky asks her what's bothering her, she tells him she's never been in a man's apartment and knows that he does dirty work for Gazzo. Rocky tells her he's not a thug and begs her not to leave, confessing he's wanted them to be together since 5^th grade. He promises her that he will look after her ("Adrian"). They kiss.

Gazzo corners Rocky as he's going into the gym and asks him why he isn't doing the work he's supposed to do for him ("Wanna Know Why"). He tells Rocky he doesn't have a shot at boxing and that this job is all he has. Rocky enters the gym, and Mickey tells him that Apollo Creed's team want to meet with him. Rocky asks Mickey why he doesn't take him seriously. Mickey tells him it's because he's wasting his talent helping a thug like Gazzo.

Rocky meets with Miles Jergens, Apollo's promoter. Rocky thinks he's looking for a sparring partner for Apollo, but Jergens tells him they're offering him a spot in the championship match with a huge cut of money, win or lose. Rocky is unsure so Jergens gives him time to think. Rocky realizes this is his one shot at proving himself ("Fight From The Heart").

Rocky agrees to fight Apollo. Philadelphia is abuzz with the news of the match and that "One of Us" has a shot at the championship.

Act Two

The big fight is just weeks away, and Rocky is up early training ("Training Montage #1"). Back at his apartment, he gets a visit from Mickey, who offers to be his manager. Mickey tells Rocky about his glory days as a boxer ("In The Ring"). Rocky at first dismisses Mickey but ultimately comes around and agrees to train with him.

Mickey trains Rocky ("Eye of the Tiger") and advises him to slow down with Adrian so he doesn't get distracted. Adrian can sense Rocky getting distant. Mickey tells Rocky not to have any publicity leading up to the fight, but Paulie manages to bring a reporter and TV crew to catch him while he trains.

On Christmas Eve, Adrian, Gloria, Joanne, and Angie are closing up the store. Paulie drunkenly comes in, only to be turned away. The ladies lament needing a break from all the bad men in their lives ("Holiday (Reprise)").

Rocky comes home to find Adrian has added some nice touches to his apartment, including a Christmas tree. As they decorate the tree, they realize this is the happiest they have ever been ("Happiness"). Their moment is interrupted when Paulie barges in. Jealous that Adrian spends all her time with Rocky now, he demands that she comes home with him. Adrian, finally fed up, tells Paulie "I'm Done".

On New Year's Eve, the streets of Philadelphia are filed with anticipation for the big fight - and so are Rocky and Apollo Creed ("Southside Celebrity"). Rocky and Mickey watch Apollo's old fights for preparation. Rocky comes home to Adrian and tells her he can't beat Apollo. Adrian tells him she can't go to the fight and see him get hurt in the ring. Alone, Rocky musters his courage and prepares for the fight ("Keep on Standin'").

It's time for the big fight. Rocky, Apollo Creed, and their entourages enter the ring ("Undefeated Man"). The two fighters are finally face to face, and the fight begins ("The Fight"). Rocky has a tough start but manages to land a good hit on Apollo at the end of Round One. At the end of Round Two, Apollo almost knocks Rocky out. Rocky is hurt but his confidence is stronger than ever. By Round Ten, Apollo has a broken rib and Rocky a broken nose. Rocky resolves to keep fighting. The fight brutally continues, with the two fighters being pushed to the limit while Adrian watches from the crowd. At long last, the fight ends with Rocky barely standing and a split decision from the judges. As Apollo Creed is declared the champion, Rocky calls for Adrian, who runs to his arms.