The story follows Ryuichi Kashima and his infant brother, Kotaro, who are orphaned when their parents die in a plane crash.
The original Gakuen Babysitters manga is serialized in Hakusensha’s LaLa shōjo manga mangazine.
Morinomiya agrees to become the legal guardian of the Kashima brothers until they are old enough to live on their own, but in exchange Ryuichi has to work as a baby-sitter at the Morinomiya Academy.