Ryuugasaki Mamoru is a childcare worker who loves kids, but due to various circumstances has lost his self-confidence. On his way home from work, he hears the voice of a child asking to be saved, and when he answers the plea, he gets sent to another world. He promptly gets run down by a pitch black dragon, resulting in him falling off a cliff and losing consciousness. When he next opens his eyes, he finds himself in a facility designed to care for young dragons. Mamoru starts working there as a staff member under the condition that they certify his identity. On one hand, he’s able to make use of his experience as a caretaker and prove himself, but on the other hand he has to get along with the fickle and hard-to-please black dragon, Kokuyou.