Mamoru Takagi s best friend, Junichiro Sasakura, suddenly dies from cancer, leaving behind his twin children, Kaoru and Tomoki. The children s mother had already abandoned them when they were young, and they have no other dependents left. The twin s relatives argue over who will take responsibility for them, and in the end, the twins are separated. However, the twins are extremely close, and both run away from their respective foster families. Marumo manages to find them, and after a brief struggle to bring them back, Marumo gives in and agrees that the twin can stay with him. Along the way back, a dog, which has been following Tomoki, follows them back to Marumo s house.
However, Marumo has no parenting experience and makes a lousy parent. He manages to care for them, together with the help of his landlord and the landlord s daughter. Over time, they face many challenges, with Marumo trying hard to balance his time between his work and taking care of the twins.