In the celestial realm, God (voiced by Gene Hackman) returns from a lengthy 25-year retreat, now infused with a profound appreciation for Shakespeare, while growing increasingly frustrated with the widespread malevolence on Earth. In a fit of exasperation, He resolves to obliterate humanity with a catastrophic flood, despite the appeals of His loyal angels: Earl (Scatman Crothers), Charlie (Charles Durning), Gonzales (Castulo Gurrera), and Ruth (Beatrice Straight), who adamantly argue that glimmers of goodness still exist among humans.
To demonstrate that humanity is worthy of saving, God challenges His angels to provide an example of the average person. They randomly select Zack (John Travolta](/actor/john-travolta)), a hapless inventor struggling to gather $13,464 by six o'clock that evening to appease loan sharks Stuart (Richard Bright) and Oscar (Vincent Bufano), who threaten to mutilate him if he fails. In a desperate attempt to secure the funds, Zack wields a pistol and storms into a bank, demanding $15,000 from a captivating teller named Debbie (Olivia Newton-John). During this chaotic encounter, Debbie flirts with him and hands over a bag of cash, but fate turns when Zack discovers the bag is filled not with money but with stark, blank paper.
Meanwhile, Debbie confesses to her roommates Terri (Toni Kalem) and Ron (James Stevens) that she was dismissed for her playful interaction with the bank robber. The story continues as their landlord, Mr. Chotiner (Jack Kehoe), demands his rent; Debbie cleverly pays using the very money she illicitly took from the bank.
That night, the vicious loan sharks chase Zack through the bustling streets of New York. As he leaps onto a moving delivery truck, an unexpected halt sends him crashing into Debbie, solidifying their paths. Back in heaven, God takes Zack's reckless actions as proof of His complaint regarding humanity. The desperate angels propose a chance at redemption to God, suggesting that if Zack makes the ultimate sacrifice for another, humanity may be spared. God raises the stakes further: both Zack and Debbie must sacrifice everything for one another, or face the impending flood within a week.
Unbeknownst to Zack and Debbie, the angels descend to Earth disguised in various forms. The cunning Devil, now adopting the name Mr. Beasley (Oliver Reed), plots to ensure the couple's downfall. As the cosmic game plays out, the angels work to reverse the course of events, allowing Zack to evade the loan sharks while Beasley plots misfortune.
The following day, Zack uncovers the scandal of Debbie's theft from a newspaper article and tracks her down to an acting workshop, where she is confronted with her past. During the session, her performance falters until she catches sight of Zack, prompting a stunned reaction that draws applause from her classmates. Despite their rocky beginning, a budding romance develops as Zack learns of Debbie's aspirations of becoming a Broadway actress, while he reveals his own questionable history of crime for his outlandish invention—edible sunglasses.
In a twist of fate, the loan sharks invade their serene dinner at the Plaza, leading Zack to make a daring escape attempt that draws even more chaos when Beasley intervenes. Throughout it all, the struggle between the angels and the Devil escalates; Zack and Debbie's bond deepens amidst the tumult, even as they face multiple arrests and betrayals.
Amidst struggles and misunderstandings, divine interventions lead to Debbie discovering she lost the role she longed for, while Beasley and the loan sharks threaten their happiness at every turn. When a gunman takes Debbie hostage, Zack's fierce love propels him into action, suffering a grave wound in the process. As he seemingly passes away, Debbie's heartfelt declaration of love breathes life back into him.
In a final showdown, the angel Charlie confronts Beasley in a tense street encounter, yet allegiance forms between the two. As Zack and Debbie step out triumphantly into a crowd of joyful onlookers, their surprising journey culminates in an unexpected gift: a collection of Shakespeare plays from Charlie, leaving them to reflect on the wild week they've experienced together.
