We always want what we can’t have. Ai (Anna Yamada), a cool and calculating high school senior, has good grades and navigates the social scene with ease. But when she discovers that her crush, classmate Tatoe (Ryuto Sakuma), is in a secret relationship with another student, something wicked stirs inside her.
She pinches the love letters that Tatoe has been receiving from his sweetheart, Miyuki (Haruka Imou) — a frail and friendless diabetic — and sets out to insinuate herself into both of their lives. But is it unrequited love that’s driving her, or avarice?
Rin Shuto’s “Unlock Your Heart” has the surface trappings of a paint-by-numbers teen drama, but its pink-hued visuals conceal an acid core. That’s due in no small part to the film’s eponymous source novel by Risa Wataya, whose piquant tales of unconventional women have already been adapted to winning effect in Akiko Ohku’s “Tremble All You Want” (2017) and “Hold Me Back” (2020).