Hideout by Masasumi Kakizaki

A quietly desperate man, pushed past his breaking point by marital betrayal and personal failure, commits a violent act and retreats to a remote dwelling to conceal his crime. Isolated from society, he is forced to confront guilt, paranoia and the unraveling of his own mind as past choices and inner demons close in. The story is a tense psychological portrait of obsession, secrecy and the human capacity for self-destruction.