Seasons & Episode
After having Iroha spy on Shūsuke and Mayuka the previous night, Nao tries putting on black pantyhose and clinging onto Shūsuke as he sleeps. Iroha and Mayuka later arrive, leading to an awkward confrontation. Mayuka ends up questioning what Nao and Iroha see in a pervert like Shūsuke, mentioning her affection towards him is different from theirs. Later that night, Mayuka gets Shūsuke to read through one of her BL books, which ends up traumatizing him.
Shūsuke and his friends go on a trip to Akihabara in search of adult goods while Nao and Iroha decide to follow them. After visiting an adult DVD store, the group gets into an argument about their desired fetishes and break off in search of them, leaving Shūsuke alone. However, they soon come to apologize to each other and go to a maid café holding a 'little-sister' service.
Shūsuke goes to a Matsuri festival with Nao and Iroha, who compete with each other to try and seduce him. Meanwhile, the A.G.E Explorers go on a quest to find a legendary pornographic treasure and proceed to drag Shūsuke away to join them. However, the treasure they find contains zoophillic porn that proves too intense for them and they run away, with Shūsuke picking up Nao in tow. After watching the fireworks with Nao, Shūsuke goes to deliver some BL books to Mayuka, who once again becomes enthralled by his nipples.
Nao Takanashi loves her brother Shūsuke despite the incest taboo. Nao thinks that Shūsuke is her blood relative, but in fact she is an adopted daughter, whose parents have died. After Nao learns the fact, she wants to fall in love normally with Shūsuke because siblings by adoption can marry under the family law in Japan. However, she finds herself competing with Shūsuke's childhood friend, Iroha Tsuchiura, and his class president and yaoi lover, Mayuka Kondō.