Horror comics author Junji Ito has recently purchased a new house and has decided to invite his girlfriend to move in with him. However, when she moves in, she comes with two cats - Yon, a strange-looking white cat with a ghastly fur pattern on its back that resembles a skull, and Mu, Yon's cute counterpart and playmate. This is the diary of the author's life as he tries and often fails to connect with his two feline guests.