Rin has been watching her son grow up healthily. He has overcome his rebellious phase, is good at studying, and has a good friend, Takeshi. One day, Takeshi comes to visit the house for the first time in a long time. Takeshi, who has been in love with Rin for a long time, accidentally finds out about Rin's weakness. When Takeshi, whose feelings for her that have been building up for many years, get out of control, Rin offers herself to him...