Sayaka, daughter of a yakuza family, takes in Bow, a bull terrier, after finding him stray. Her father initially opposes keeping the accident-prone dog but reverses his stance after Bow saves the life of his gang's boss, securing Bow's permanent place in their home.

As Bow's primary caretaker, Sayaka shares his daily mishaps and neighborhood adventures, frequently involving her family, particularly her father who maintains an antagonistic yet accepting relationship with the dog. Episodic events feature her activities like attempting cooking challenges, visiting theme parks, dealing with illnesses, experiencing school events, and undertaking journeys with Bow, including a countryside trip marked by unexpected difficulties.

In the movie adaptation, set in a prehistoric era where her village faces starvation, Sayaka joins Bow, Inugami, and Sabu on a journey prompted by a prophecy from Inugami’s grandmother about a chosen one saving the village with a great animal. She actively participates in efforts to capture a mammoth, with Bow contributing his characteristic chaotic behavior. Sayaka assumes a leadership role in this quest, driving efforts to resolve the village's crisis despite Bow's antics introducing further complications.