In the film, the story unfolds on November 9th in the arid landscape of Palm Springs, where a seismic event causes the earth to split open, revealing a mysterious glowing cave. The narrative follows Nyles, voiced by Andy Samberg, who awakens in his hotel room alongside his girlfriend, Misty, as they prepare to attend the wedding of Misty’s best friend Tala and Abe. Their encounter is marked by awkwardness and tension, exemplified when Misty leaves abruptly after an unsatisfactory intimate moment, leaving Nyles seemingly detached and disillusioned with life.
Later, Nyles reappears at the wedding dressed exactly the same, exhibiting a casual and almost apathetic attitude. As Misty gives her speech and Howard, Tala’s father, prompts her sister Sarah (played by Cristin Milioti) to speak, Nyles unexpectedly delivers a flawless wedding speech, stepping in to help Sarah when she panics. A peculiar and unsettling figure, Randy, tries to dance with Sarah, whom he is turned down by, only for Nyles to approach her instead. Their flirtation deepens as they share a brief kiss, but this moment is interrupted when Nyles is shot with an arrow during an attempted escape, chased by a man named Roy (played by JK Simmons), who fires another arrow into Nyles’s leg.
Desperately seeking safety, Nyles drags himself into a luminous cave, warning Sarah not to follow him. She disregards his plea, and he is suddenly pulled into the glowing light, waking to find himself trapped in a never-ending time loop. Every day resets to the same point, and Nyles goes about his routine with a profound sense of hopelessness—often lounging in a pool wearing a Hawaiian shirt and shorts, talking with a groomsman named Jerry.
Sarah, confused and alarmed, begins to realize the gravity of her situation when she follows Nyles into the cave and wakes up once again on the morning of the wedding. Her frustration with the repeating cycle grows, culminating in a desperate drive back to Austin, only to wake up on the same day repeatedly. The situation worsens as she confronts Nyles about the anomaly, leading to a revelation that Nyles has been living in this loop for so long that he's become resigned to the meaningless repetitions, having even attempted to end his life multiple times.
As Sarah tries to understand her predicament, she develops a theory that escaping the loop requires genuine selflessness and acts of goodness. Their attempts to break free fail repeatedly, including Sarah whispering something devastating to Tala, but the cycle continues unabated. In their shared exploration of the endless day, they indulge in wild antics—stealing a plane, executing a choreographed dance, tricking Randy, sabotaging the wedding cake with a bomb, and hosting countless parties.
Their bond deepens as they spend more time together, with revelations about past failures and secrets surfacing—such as Nyles’s casual confessions about his promiscuity and a humorous comment about Howard, which turns out to be a joke. Despite their growing connection, Sarah struggles with morality and the question of whether their feelings are real or just products of the loop. She believes that the only way out may be through selfless sacrifice and ultimately tries to manipulate Tala into sabotaging the wedding, but her efforts are unsuccessful.
In a moment of intense determination, Sarah immerses herself in scientific research, driven by her past heartbreak and frustration. Utilizing her newfound knowledge of quantum physics, she devises a risky plan: to detonate the cave’s explosives while both are inside, hoping this will finally free them from the endless cycle. As the day of her planned escape approaches, she confesses her feelings and the depth of her connection to Nyles, who admits he loves her. However, she questions whether their feelings are genuine or just a result of their repeated encounters, revealing her desire to break free from the loop and start anew elsewhere.
Despite Nyles’s pleas and love for her, Sarah chooses to leave, calling him to follow her into the cave to escape together. He hesitates but ultimately respects her decision. As they walk toward the cave’s entrance, Sarah ignites the explosives, triggered by her hope for liberation. The explosion engulfs them, and their consciousness seems to drift into the unknown as they float in a pool at a safehouse, hinting that they may have escaped the loop, though not without uncertainty.
The film concludes with a mid-credits scene where Roy, arriving at the wedding, acknowledges the success of their plan after Nyles's amnesia—realizing that their scheme worked in a mysterious, unpredictable way, leaving an open ending to their fate and suggesting that the cycle might have truly ended.
This story is a profound meditation on love, regret, and the desire for redemption, wrapped in a surreal, humorous, yet emotionally charged narrative.
