Saburo (Renji Ishibashi) spends his spare time creeping into the attic of the communal building where he lives and crawling across the beams to access his neighbours' roof space, where he spies upon them through handy peepholes in the ceiling.
Among those he watches is Minako, the bored wife of a successful businessman, who has taken a room in the complex for her adulterous trysts. When Minako notices Saburo peering down on her during sex, she finds the experience so exciting that she kills her partner, a Pierrot clown, in the throes of passion-an act that spurs Saburo on to commit his own murder.
Like Rampo Noir, the only other film based on a Rampo Edogawa novel that I have seen so far, Watcher in the Attic is a thoroughly tedious and pretentious art-house affair that, despite its salacious subject matter manages to bore more than it excites. With plenty of female nudity (primarily from star Junko Miyashita) and some profoundly weird moments of erotica (including a man who hides inside an armchair for kicks and a naked woman dressed as a stag), plus a relatively short runtime of 76 minutes, this should have breezed by; instead, the film is torturously slow, director Noboru Tanaka testing the viewer's patience to the extreme with his repetitive, soporific style of storytelling.