Secret Sorrow of the Siblings

Secret Sorrow of the Siblings is a Japanese adult visual novel with an incest theme. The player controls Kaito Ootori, the nerdy and introverted older twin brother of the popular and athletic Rikuto. Late one night, Kaito overhears strange noises coming from Rikuto's room, and upon peering through the gap in the door, discovers Rikuto being fellated by their younger sister Arisa. Overcome with jealously and rage, Kaito fetches his smartphone and uses it to record their tryst, intending to use the video to blackmail Arisa into giving him the same treatment and to give Rikuto the punishment he deserves.

The gameplay consists of reading through the story, interacting with characters represented by illustrated sprites, and periodically making choices that may influence the development of the story and determine what kind of ending the player gets. The game features voice acting for Arisa and contains explicit depictions of sexual encounters.