Nobody expects to become an addict. But the opening scenes of Rikiya Imaizumi’s “In Those Days” show with chilling precision how easy it is to get hooked on the bane of contemporary Japanese society: idol pop.

Based on a memoir by musician and author Mikito Tsurugi, this bittersweet comedy-drama captures the heyday of the Hello! Project idol collective, whose popularity in the 2000s paved the way for the full-spectrum dominance of idol group AKB48 during the following decade.

It’s 2004 in Osaka, and Mikito (Tori Matsuzaka) is down on his luck. He’s flunked his university entrance exams, his rock band ambitions aren’t working out, and his career prospects don’t look much rosier. So when a concerned friend slips him a little pick-me-up — a DVD of pop idol Aya Matsuura — he’s easy prey.