After falling deeply in love and getting married, Miyu becomes the stepmother to her husband's son, Hajime. When Hajime suffers an accident that leaves him injured and confined to home recovery, Miyu dedicates herself to his care, enduring his spoiled and demanding behavior—all in hopes of earning her husband's approval. However, with no outlet for her own sexual desires, she finds herself trapped in a cycle of nightly frustration. One day, while routinely wiping Hajime's body, he suddenly says, "Stepmom, touch my cock. Isn't this what stepmoms are supposed to do in situations like this?" Torn and hesitant, Miyu ultimately gives in, overwhelmed by compassion for his suffering—and crosses the line.