Yoto Izumi, a good-natured clerk at a pet store, becomes a pet caretaker for the wealthy Kiriyama family.

However, the reclusive head of the family, Shigenobu, is cold-hearted and hates people.
One day, dozens of goldfish in the store are killed by someone. Shishin, who loves animals with all his heart, sets out with Izumi to find the murderer. Various cute animals appear, including cats, dogs, and even iguanas!

This is a heartwarming mystery in which these two mismatched characters explore the cases and bonds between humans and their pets!