It's 6 p.m. somewhere in Toronto on the last day of the world. Although the cause for the end of mankind is never disclosed, everyone seems to know it will occur at midnight, although reactions vary from person to person.
Patrick Wheeler (DON McKELLAR), still melancholy following the death of the woman he loved, reluctantly goes to see his parents (ROBIN GAMMEL & ROBERTA MAXWELL) for "Christmas" dinner although it's not that time of year. While his sister Jennifer (SARAH POLLEY) and her boyfriend Alex (TRENT McMULLEN) plan to spend their last hours partying, Patrick wishes to stay home by himself, much to the dismay of his parents.
Meanwhile, Sandra (SANDRA OH) is trying to get home to her husband so that both can commit suicide before the unknown event claims their lives. The only dilemma is that her car has been disabled and bus drivers are nowhere to be found, thus creating an obstacle for her attempt to get across town.
Craig (CALLUM KEITH RENNIE) has a different plan, however, as he hopes to act out his many varied sexual goals and desires, including sleeping with his former French teacher, Mrs. Carlton (GENEVIEVE BUJOLD), a hooker, a virgin and even his old friend Patrick if he can convince him.
Then there's Duncan (DAVID CRONENBERG), a gas company executive who's methodically calling his customers thanking them for their patronage and providing reassurance that they'll keep providing service as long as they can, all while Donna (TRACY WRIGHT), a thirty-something virgin and his lone remaining employee, faithfully stands by.
As the hours count down toward the end of life at midnight, this disparate group of people tries to cope with their last night and end up interacting in ways they hadn't imagined or planned.