The story follows two brothers trying to support their mother, who has become depressed after her divorce. However, the emotional wounds run deep, and before long, the eldest son, Atsushi, catches her masturbating out of loneliness. Overcome with arousal, Atsushi embraces his mother and says, "If you're that lonely, let me take care of you," giving rise to a forbidden relationship between them. When their secret is discovered by the younger brother, Kenji, a new crisis unfolds...