After successfully completing an important company project, Sakurai and his colleague Kazama decided to celebrate their hard work by having a drinking party at Kazama's place. Since it was nearby, the two naturally gathered there. However, after drinking too much, they got into a heated argument over a trivial matter, causing a minor conflict. Though the situation was eventually calmed down, Sakurai learned that Kazama was married to a big-titted wife named Yumi. Overcome with jealousy, Sakurai could no longer suppress the hidden desires within him and began sneaking into Yumi's bed at night.