On a trip, Akane Moriyama is invited by a man she meets by chance, leading to her first sexual experience. Her pure, untouched body is thrust into the adult world with shocking intensity. Her heart trembles with unknown pleasure, her body moving instinctively. Wrapped in the man's warmth and discovering the joy of intimacy for the first time, she gradually transforms, embracing more mature emotions. Soon, a journey across the sea begins.