Inu to no Hibi

Ryuuhei made a promise to his father: to protect Nao, even though Nao is almost ten years older than him. Now Nao is approaching thirty and wants some space, but Ryuuhei is determined to keep his word. As their daily life unfolds, the gap between them becomes harder to ignore.

Ryuuhei must figure out what protecting Nao really means when Nao is old enough to take care of himself. Their relationship is put to the test as Ryuuhei struggles to balance his promise with Nao's need for independence. Can he truly give Nao the space he asks for, or will his devotion only push them further apart?