Rare is the child who hasn’t lain awake at night, terrified by the monster they imagine is lurking beneath their bed. But in a country where many people grow up sleeping on futons, such fears are perhaps less deeply rooted. That would explain why, in “Under Your Bed,” nobody ever thinks to look in the vicinity indicated by the film’s title.
If they did, they’d immediately notice Naoto Mitsui (Kengo Kora). When we first meet this introverted loner, he’s taken up residence beneath the mattress of an old university acquaintance in her minimalist suburban home, where there isn’t nearly enough clutter to convincingly conceal his presence.