The best sci-fi films tend not to be the ones with the biggest budgets but the smartest ideas. Junta Yamaguchi’s “Beyond the Infinite Two Minutes” (2020) is a prime example: a time-travel movie whose concept (a mysterious live video feed that looks two minutes into the future) was as ingenious as its execution (one location, one continuous shot).

Originally released during the early days of the COVID-19 pandemic, the low-budget indie feature has since acquired a cult following to rival Shinichiro Ueda’s “One Cut of the Dead” (2017), its most obvious precursor.

Rather than attempt anything radical for their follow-up, Yamaguchi and his more experienced screenwriter, Makoto Ueda, have opted for more of the same. But while “River” isn’t quite as distinctive as the duo’s previous film, it manages to evoke a similar charm by treating its heady concept in a determinedly down-to-earth fashion.

That’s a hallmark of Ueda’s work: His other credits include quotidian sci-fi charmer “Summer Time Machine Blues” (2005), suggesting that he’s the go-to guy for all your garden-variety temporal paradoxes.

In “River,” when the staff at a traditional inn discover that they’re stuck in a two-minute time loop, their first thought is to attend to their guests. Fortunately, it’s the middle of the day so the place is nearly empty — there’s just a couple of old friends having a boozy reunion and a serial writer fretting about his next deadline while his editor hovers.

It doesn’t take long for room attendant Mikoto (Riko Fujitani) and her colleagues to realize that they can still recall what’s happening each time the clock resets, or that the effects of the loop are confined to a limited geographical area. However, coordinating any kind of response is difficult when they have to rush between multiple floors and buildings just to have a confab.

The film’s attention to such practicalities is a big part of its appeal. Yamaguchi reinforces this by staging each of the two-minute sequences in a single, breathless take before fading out to find Mikoto right back where she started.

The cast, many of them stage actors who also appeared in “Beyond the Infinite Two Minutes,” seem determined not to let the energy levels sag. It’s maddeningly repetitive but never boring, buoyed by an infectious communal spirit — like “Groundhog Day” (1993) done in the style of a charity telethon.

While the inn’s metaphysically inclined sous-chef (Yoshifumi Sakai) tries to find a way to break the cycle, Mikoto deduces that she’s the one who caused it. Her crime: praying to the goddess of the local shrine to make the river stop flowing in order to prevent her coworker and unrequited crush, Taku (Yuki Torigoe), from moving to France.

However, it turns out she isn’t the only person wishing to put time’s relentless march on hold. The actual solution proves to be even more absurd, though the characters — as with everything else in this delightful caper — take it in stride.

Given the recent popularity of time-loop narratives, the low-key humor and creative constraints of “River” are what ultimately makes it stand out. Unlike Ryo Takebayashi’s slicker, more visually witty and more strongly cast “Mondays: See You ‘This’ Week!” (2022), it also knows how to end.

River (Riba, Nagarenaide Yo)
Run Time86 mins.
OpensJune 23