Jess is ready to paint the town purple when a chance encounter finds her and best friend Cece invited to a once-in-a-lifetime mansion party thrown by music legend Prince, guest-starring as himself. Not wanting to miss out on the fun, Nick, Schmidt, Winston and Coach are determined to crash the festivities, building toward an unforgettable ending.
Jess (Zooey Deschanel) and Cece (Hannah Simone) almost get run over by a black SUV (with Minnesota plates). Feeling bad about it, the driver who it turns out works for Prince, invites the pair to a party at Prince’s L.A. house.
As Cece and Jess leave for the party in a limousine, Jess' boyfriend Nick (Jake Johnson) says he loves her for the first time. She replies speechlessly, with 'pistol hands', shooting at him.
While the girls get into the party, Nick and his mates discuss about the declaration and decide they have to crash the party in order for Nick to clarify things with Jess. When they succeed Jess and Nick seclude in the mansion’s gardens to talk in private, when Prince shows up. Jake reluctantly lets Prince and Jess have some private time together, gets back to the party and starts to drink.
Meanwhile, Prince invites Jess to taste his chef’s pancakes, before having a redress session with her, a ping-pong game (he wins 15-0), a love mantra experience surrounded by candles, a dark closet scaring spoof and a butterfly pet encounter in the gardens. Finally he lets her go, pushing her to go back to Jake and declare her love to him.
Back to the party, Jess follows Prince’s advice and tells Nick she loves him. As the pair kisses, Prince appears onstage and invite Jess to join him onstage to sing his new song. Prince’s band and Jess' friends join onstage to dance.
Back home, the gang wonders if the events were real, how where they’ll go from there and where has Cece disappeared. It appears that she’s still at Prince’s mansion, teaching him a ping-pong lesson.