Mai Hasegawa, a married woman, invites her friend and her friend's son over to her home, but things take an unexpected turn. Without realizing it, she becomes the object of desire for her friend's son, Yuta, who is captivated by her big tits. Day after day, as Yuta affectionately clings to her and gropes her breasts, Mai finds herself immersed in pleasure. However, one night, upon seeing Yuta's erect cock, Mai's restraint shatters, and she resolves to accept his nighttime advances. The two passionately indulge in sex, her large breasts bouncing with each movement. Sneaking around her family, they begin a secret, intimate relationship.