A few months after marrying a man with a child from a previous marriage, Reina has been feeling awkward about her life, as she has not yet opened up to her stepson, Ippei. One day, she witnesses Ippei masturbating day and night... In the end, she ends up helping him release his sexual desire. This leads to a closer relationship between the two, and Reina feels happy to be called mother. However, Ippei, who has a strong sexual appetite, is not satisfied with just one or two ejaculations, and she has to help him with the urination process many times...