At a university in Kagawa Prefecture, the science-fiction club and the photography club share a busy, cluttered clubroom, hinting at the creative mix of curiosity and camaraderie that defines campus life. On August 19, 2005, the sci‑fi crew tosses a casual game of baseball while Yui Ito from the photography club quietly captures the moment, their different passions weaving together a shared memory. After the game, the sci‑fi group heads to a bathhouse, leaving Yui Ito and Haruka Shibata to develop the photos, a quiet routine that soon becomes the backdrop for something stranger than a simple snapshot. While the two women wash away the day’s salt and sweat, a tetchy moment over a missing bottle of Vidal Sassoon shampoo stirs up a small storm in the bath—the kind of petty conflict that signals that something more is bubbling beneath ordinary life.
Back in the clubhouse, Takuma Komoto Takuma Komoto quietly plots a small, hopeful gesture—asking Haruka out after buying tickets for a sci‑fi B movie. But Haruka misreads his intentions, thinking he already has a girlfriend, which adds a layer of ambiguity to their budding dynamic and leaves Komoto standing uncertainly with his plans. The mood takes a bizarre turn when his friends act inexplicably evasive about his whereabouts and then insist he dance naked, a prank that escalates the sense that something is off beyond ordinary teenage shenanigans. When Coca‑Cola spills onto the air‑conditioning remote, the climate inside the room shifts from playful mischief to practical problem‑solving, and the group hands the broken device to their club advisor, Kotaro Hozumi, known to the students as “Hoze,” hoping he can repair the malfunction.
The following day, Haruka and Yui resume developing their photographs, and Haruka notices a mysterious figure peeking from a shadowy corner of a clubroom photo. At the same time, the sci‑fi club discovers a strange boy lingering in the room, who bolts away in a blur, leaving behind a curious object: a time machine. Assuming it’s a prank, the group experiments with the device by placing Atsushi Soga on it, only to realize it actually works. Atsushi Soga travels back to August 19 and is revealed to be the figure the photography club spotted, a revelation that kicks off a chain of experiments that stretch the boundaries between time and memory.
This discovery prompts Daigo Ishimatsu, Kotaro Hozumi (the club adviser, “Hoze”), and Shunsuke Koizumi to travel back to yesterday to steal the remote and prevent it from ever breaking in the present. But once they arrive, curiosity eclipses intention, and the trio abandons their original mission, choosing instead to explore the past and the world it reveals. Meanwhile, in the present, a mysterious boy introduces himself as Tamura, a sci‑fi club member who traveled from August 20, 2030. Like the others, he was dragged into the machine by peers and does not know where it came from. The remaining members—Haruka, Atsushi Soga, Yui Ito, and Takuma Komoto—decide to guide him on a tour of what lies in the past.
During this journey, they encounter Hoze, who explains a chilling consequence: changing the past can trigger a grandfather paradox and threaten the entire universe. Realizing the gravity of their actions, the team rushes back to ensure Ishimatsu, Koizumi, and Niimi do not alter history. Ishimatsu and Koizumi return to the present, but soon bring Tamura back after being warned of the danger. When they locate the time machine again in the club room, Soga and Komoto set off for August 19, but Soga’s bold plan leads him to 1906 instead of merely repairing a broken remote. He faces the surreal challenge of a swamp‑filled town and is mistaken for a Kappa by the locals, a twist that embeds ancient folk beliefs into the evolving science‑fiction narrative.
Back in the bathhouse, Komoto tracks down Masaru Niimi and, in a twist, learns that Niimi was the one who took the shampoo in the first place. With the remote now missing, Tamura travels forward to December 19, 2030 to retrieve the device from the future so that the past cannot be rewritten. The group, resolved to return to August 20, 2005, boards the time machine together, but it cannot accommodate everyone. Komoto is ejected and remains stranded in the past, where he encounters his past clubmates. They mistake him for someone’s boyfriend due to a voice message sent to the “present Soga” that the “past Soga” received, leading to a tense chase that ends with Komoto hiding inside a locker. In a parallel thread, the present club members return to find Komoto missing, only to discover he has, in fact, spent the entire day hidden in the locker.
A dog digging up the remote and a fortunate turn of luck with a century‑old rescue of the remote by the earth itself allows the group to fix the air conditioning again. Tamura makes a final run back to 2030 to retrieve his camera, only to realize he forgot it and then discover a camera with a familial resemblance in Haruka’s possession. This clue, together with Tamura’s assertion that his mother attended the same college, leads Yui Ito and Haruka to the startling conclusion that Tamura is Haruka’s future son, weaving a poignant, almost mythic thread through time itself.
The events inspire Professor Kohtaro Hozumi to begin pursuing his own time‑travel project, hinting at a possible origin for the mysterious machine and leaving open questions about causality and the future. In the final turn of emotional weather, Komoto’s earlier confession about a supposed girlfriend collapses into a truth that clears the air between him and Haruka, who agrees to go on a real date. Yet Komoto remains quietly thrilled and contemplative, wondering how his name might evolve in a world where time travel has rewritten the rules of how people connect.
