Marumo no Okite

Mamoru Takagi's best friend suddenly dies from cancer, leaving behind his twin children, Kaoru and Tomoki. The children's mother had abandoned them when they were young, and they had no other dependents left. The twins' relatives argue over who will take responsibility for them. 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 twins can stay with him.