The film unfolds in three acts presented in reverse chronological order, beginning with Act Three – Thanks Chuck. In the classroom of Marty Anderson, a teacher, students are alerted to news of an earthquake via their phones. Shortly after, they realize the internet has vanished, leaving them disconnected from the world. Among the parents trying to reach out is Josh, who expresses his despair over his wife's departure and the strange fact that popular sites like Pornhub are inaccessible. Meanwhile, disasters begin surfacing globally. Marty notices increasing advertisements and billboards dedicated to a man named Charles "Chuck" Krantz (Tom Hiddleston), thanking him for “39 great years.” As his ex-wife, Felicia Gordon, a nurse, overhears a radio announcement for Chuck, she and Marty start speculating whether they are facing the apocalypse. After their call, yet another commercial appears on Marty's TV in gratitude towards Chuck.
As more bizarre happenings occur, Gus Wilfong informs Marty that a sinkhole has opened nearby, hindering travel and prompting discussions about the possible end of times. In the sky, "Thanks Chuck" is etched out by an airplane. Felicia and her colleague Bri observe an unsettling number of empty hospital beds, even as monitors indicate active lifelines. Marty, unable to contact Felicia due to dwindling service, takes a stroll and meets Sam Yarbrough, an undertaker who shares cryptic thoughts about time and an impending reckoning. As day gives way to night, Marty encounters a young girl, Iris, struggling with her skating amid blacked-out street lights, before reaching Felicia’s house where they come to terms with the looming darkness. In a hospital room, Chuck is seen nearing the end beside his wife, Virginia 'Ginny' Krantz, reaffirming their love for one another just as the scene fades to black.
Act Two – Buskers Forever introduces us through the voice of the Narrator, [Nick Offerman], to a young woman named Taylor Frank. She is a street performer who plays her drums for spare change in the town square. Simultaneously, we are introduced to Janice Halliday, whose relationship has just ended tragically via a text message. Chuck is also out during this ordinary day, blissfully unaware that in six months he will succumb to a brain tumor. As Taylor plays an energetic tune, she captures Chuck's attention, prompting him to dance, which draws a captivated crowd. Eventually, he invites Janice to join him, and though initially hesitant, she too embraces the moment, showcasing their dance moves to the audience's delight. After their performance, Taylor offers to share her earnings with them, but Chuck and Janice graciously decline. They part ways but interestingly, Chuck reflects on his uncharacteristic burst of joy, unaware of the heavy fate that awaits him—losing many of life's simple pleasures.
Act One – I Contain Multitudes delves into young Chuck’s life, where he faces profound loss at a young age when his parents and unborn sister perish in a tragic car accident. He then moves in with his grandparents, Albie and Sarah, who each cope with the tragedy in contrasting ways; Albie turning to alcohol while Sarah finds solace in music, nurturing Chuck’s love for dance and classic musicals. Albie forbids Chuck from entering a mysterious locked room, claiming it holds dark secrets relating to premonitions of death. After the passing of Sarah, Albie’s addiction worsens until the day he dies from a heart attack, leaving the young boy isolated. As a teenager now played by Jacob Tremblay, Chuck discovers the hidden room and is confronted by the adult version of himself on his deathbed. This shocking vision inspires him to strive to live a life enriched with experiences, as he is reminded he “contains multitudes” of potential and passion. Throughout his journey, Chuck not only navigates personal grief but also learns the importance of embracing his unique identity and the moments that define him.
