Shota visits his relatives, the Nii Zuki family, for summer vacation and instantly falls for his cousin Sanae, who has just returned from swim practice. Mesmerized by her now voluptuous figure, Shota becomes completely infatuated with her large, alluring breasts. Later, taking advantage of a tutoring session, he starts playfully teasing and groping her breasts. As the carefree days of summer unfold, Shota indulges himself, secretly enjoying the full attention of Sanae’s magnificent K-cup breasts.