Cat and Salt, or Sugar

Ichiro is a kind of hikikomori who lives with his timid mother, Keiko and his alcoholic father, essentially allowing the former to treat him like some sort of a pet and particularly a cat, as he so eloquently states in the beginning of the film. The two of them are essentially a team, and have alienated his father, whose obnoxious behaviour, however, definitely justifies their attitude. One day, while on a trip with his mother, they stumble upon an ex-boyfriend of hers, Mr Kaneshiro and his daughter, and through a series of rather illogical events, they invite them to stay in their house.