When I return to my hometown after a long time, my sister "Ai" who has been on good terms with me for a long time greets me cheerfully.That night, she said, "Onii-chan, can I sleep with you?"When she is confused, she confesses, "...I like my brother, but I know it's not cool, but...I can't control this feeling."She is puzzled by how she has grown from a child to a young girl, but her brother, who shared the same feelings, can't help but connect with her sister...