Marina and Kenji have been continuing their cuckolding lifestyle for a year now, but lately they feel their lifestyle is negatively affecting Hiroto's studies, and decide to stop Marina's sexual activities with him. Now the couple needs to find another "bull", and chances upon one Yamashita Kouichi - a retired AV actor. After Marina's first outing with him, she returns home with surprising news: Kouichi is just not that good at sex...