"It'll only be for a short time, but please take care of me." His parents are away on a trip and ask his mother's best friend, Anna, to take care of him. Koichi is Kokoro by Anna's massive breasts, which are too stimulating for an adolescent. If he misses this opportunity, he may never meet such a wonderful woman again. Unable to sit still, Koichi is driven by his worldly desires and uses Anna's underwear as a masturbation aid. However, he unfortunately runs into Anna...