The fourth OVA adaptation of Jairo's "The Summer When the Boy Became a Man" (TI Net)! His beloved older sister and his idolized erotic live video streamer. A secret story between two older sisters and a young boy... *This work utilizes in-motion technology to create a world that could only be experienced in the comic. 【STORY】 A shocking truth!? The protagonist, Kirishima Ryuki, has realized something. He begins to wonder why Reiko hasn't shown him her room for the past four years. The answer is here... He makes up his mind and opens the door, and what he finds there!? Reiko's true nature is revealed, The more he deviates from the norm, the more he realizes things and feels a sense of liberation amidst the chaos... His feelings intensify to the point of no return. Their secret continues even as they grow into adults. Includes "The Summer When the Boy Became a Man - Final Episode" from the original work: "The Summer When the Boy Became a Man"