Yumi married a man who had a son. Ryota, her husband's stepchild, had been in love with Yumi, his father's new wife, from the moment he saw her. Since he started to think of her as the opposite sex, Ryota has kept his distance from Yumi. Wanting to deepen their relationship, Yumi takes on even more of his daily needs... Ryota, who is still a virgin, cannot resist Yumi's charm and masturbates by licking her underwear. Yumi witnesses the scene in a state of surprise but excitement. Then, in a gentle voice, Yuta whispers to Ryota, "Want to know what an adult kiss feels like?"...