Known mainly as a scriptwriter, Shin Adachi has been sole director of three full-length features, two of which are about boys not yet in high school: 2016’s “14 That Night” and this year’s “Brats, Be Ambitious!”

Both films draw inspiration from the 1986 Rob Reiner classic “Stand By Me” and its story of four boys who set off on a life-changing journey. But while the earlier film was mostly about the young heroes’ comically raging hormones, this one ventures into deeper dramatic waters while subjecting its principal protagonist to a supreme test of character.

Adachi, who evidenced a dark sense of humor in the relationship comedy “A Beloved Wife” (2020), goes for full-bore melodrama in “Brats,” complete with mournful violins, parting tears and that device that never fails to draw sobs and sniffles from a Japanese audience — a frantic run after a departing train.