Graduate student Leon (Alan Solomon) summons five college students to his apartment and challenges them to participate in his latest game creation: The Great All-Nighter. He tells them about his game and instructs them to form teams. At first, the leaders refuse to play. However, rivalries between them lead all five to change their minds by the game's start time – a scenario Leon has already predicted based on his extensive planning.
Leon, as "game master", keeps track of the teams' locations with a giant map, and various radio equipment. The teams are supposed to call and check in at each clue (though many of the teams end up skipping at least one location).
The adventures of the other three teams are subplots, as well as the situation at Leon's apartment ("Game Control"). Here, along with his female assistants Candy and Sunshine (Debi Richter and Kirsten Baker), Leon monitors the progress of the game. Already unpopular with his landlady, Mrs. Grimhaus (Irene Tedrow), for the amount of noise he makes, Leon faces eviction if any of the other tenants complain. Several of them do show up to complain, but as Leon explains the mechanics of the game to them, they become fascinated with it and help run it, much to the annoyance of Grimhaus.
The game culminates in a race-to-the-finish at the Westin Bonaventure Hotel where the yellow team ultimately prevails and wins the game. A huge party consisting of all contestants and game control follows.
