Two sisters, Sumire and Ichika, who have been in love with their older cousin since childhood. Sumire, the elder sister, is mature and has a strong personality, while Ichika, the younger sister, is innocent and energetic. Since they were young, their cousin has been teasing them, and the pleasure has been etched into their small bodies. As they enter puberty, the sisters also start teasing their cousin! Using their tanned bodies as weapons, they seduce him and drive him wild with desire.