Oshima, an executive at a major corporation, worries about his idle son and arranges a match with Yu, the adult daughter of a subcontractor's manager, hoping marriage will change him. In truth, Oshima uses the arrangement to keep his favorite woman close and make her his own. He forbids his son from touching Yu during the year before their wedding. The following year he sends the son away on a five-day business trip, leaving himself alone with Yu, whose sensitive body is desperate after so much abstinence. Their five-day training life begins.