A heartfelt story of unexpected love begins with the break-up of a long-term relationship between Nick and his girlfriend Tris. Though he is heartbroken, his bandmates convince him to go to a show involving the extremely underground band "Where's Fluffy?" in New York City. Norah, a girl who goes to school with Tris, happens to be at the same concert. Although they greatly dislike each other, they share a friend named Caroline, who also attends the show. It is revealed that Norah has been taking Nick's mix CDs out of the trash after Tris discards them, and their musical tastes are remarkably similar. Wanting to show up Tris, Norah finds Nick and tells him to pretend to be her boyfriend, not knowing that he is the one Tris just broke up with. She kisses him passionately, igniting Tris's jealousy. Soon after, the mutual friend Caroline becomes embarrassingly drunk and wants to go home. Though it is Norah's job to care for her, Nick's bandmates see potential in Norah, and offer to take Caroline home for her.
Nick's bandmates, Thom and Dev, lose the confused Caroline before they manage to get her home. They meet up at another club where "Where's Fluffy?" is rumored to play. Caroline is unfortunately not there, and they end up finding her onstage at a gay cabaret, dressed as a Christmas tree. When Nick, Norah, and the others leave Nick finds Tris waiting for him on the hood of his car. Though Norah expresses that she enjoyed meeting him, Nick approaches Tris without responding. Tris tells Nick that she wants him back, and asks for a ride home and attempts to seduce him. Meanwhile, Norah spends some time with her manipulative friend-with-benefits, leaving him a large tab to pay. Nick refuses Tris and reunites with Norah, who he knows now to be a much better match for him, and they continue their search for "Where's Fluffy?".
For a film about the apocalypse, "Seeking a Friend for the End of the World" sure is finding a lot of survivors. Of course, the film is more of a pre-apocalyptic rom-com, about a man (Steve Carell) and a woman (Keira Knightley) going on a road trip to find his high school sweetheart before the planet's destroyed by an asteroid.