Nanana's Buried Treasure

Yama Juugo is a high school boy who has moved to Nanae Island, also known as the Special Student Zone, after being kicked out of the house by his father. He has chosen to begin his solo life in room 202 of the Happy House, a one-room apartment plus kitchen with separate bath and toilet, including furniture, appliances, and extras for 5,000 yen per month. But when he enters the room, he sees a girl relaxing inside, watching TV...

Juugo picks up a jewel that fell from the sky as he was on his way home from the convenience store. It turns out to be one of Nanana's Collection: the The Eye of Yuguthos. Juugo is shocked that Nanana's Collection really exists. Meanwhile, the master detective Ikkyuu Tensai and her assistant, Hoshino Daruku, pay a visit to room 202 of the Happy House in search of the stolen jewel.

After clearing the ruins in the classroom, Juugo, Tensai, and Daruku become members of the Adventure Club. At club president Yuiga Isshin's request, Juugo undergoes a trial administered by Nanana to get her to share the location of the next treasure. This complete, the Adventure Club sets off to the Rising Building. As they search for the ruins, Tensai quickly finds a certain door...

After Juugo and Tensai escape from the Rising Building, Juugo receives an email from Tensai saying that Isshin plans to sell the Wizard's Cane to Ikkaku Shunjuu.

The Adventure Club is back in action. Isshin proposes that they plan an overnight trip to a hot springs town on the west side of the island, where he suspects they'll find the next ruins.

The Adventure Club has come to a hot springs town. In the hallway of their inn, Juugo sees Yukihime with a friend of hers, but she ignores him. That evening, Isshin shows everyone the layout of the nearby house that he has brought them to explore, and Tensai pinpoints the room that the ruins are in.