For the most part, the game follows the plot of the movie: amiable banker Johnny helps his friends with their day-to-day problems while preparing for his wedding to his future wife, Lisa. When he discovers that Lisa is cheating on him with his best friend Mark, Johnny is outraged and ultimately kills himself. The game diverges from the film by only showing the events from Johnny's point of view. The player controls Johnny as he engages in activities that were only referred to in the film, such as his taking on a mystery client at his bank and his turning over drug dealer Chris-R to the police. The game also contains several in-jokes that attempt to provide backstories and account for idiosyncrasies in the film and its story. For example, a scene in the game's final level attempts to explain the inexplicable disappearance of supporting character Peter from the final act by revealing that an escaped Chris-R, in an act of revenge for his arrest, stole Johnny's car during the party and killed Peter in a hit and run.

The game begins with a prologue, showing Lisa and Denny at Johnny's grave (a statue of Tommy Wiseau) and then segueing into a level that occurs a day before the main action of the movie begins, in which Johnny learns that an earthquake has sealed San Francisco off from the rest of the state. The final level of the game permits players to "tie up" loose plot threads left hanging at the end of the film, such as the fate of Chris-R and Johnny's contentious relationship with his superiors at the bank. The game also includes an epilogue revealing that Johnny was, in fact, an alien being inhabiting a human body; after Johnny's "suicide", he returns to his mother ship, a giant mechanical spoon orbiting the Earth, and laments how he and his fellow extraterrestrials may never understand human life. Johnny and two of his fellow aliens then assume forms resembling a naked Tommy Wiseau and begin dancing, ending the game.

Should the player collect each of the hidden spoons throughout the game, rather than simply dance during the climax the aliens fire a ray gun at Earth that reshapes the planet into a giant spoon.