Yuki, the eldest son, is taking care of his four younger brothers - his biological brother, his stepbrother, his younger brother (who lives next door), and his younger brother from his previous life - in place of his parents who emigrated overseas. One day, the pranks of his younger brothers escalate, and Yuki ends up locking himself in the storeroom. When his stepbrother Chiaki comes to apologize, Yuki is seduced, but Chiaki's attitude changes completely. "I love you. I've been holding back all this time," he says, and then he does something naughty to him...!?