Now that he has some knowledge of Nanana's history and the sphere of her influence, it's not all that surprising that Juugo has found himself picking up a particularly interesting trinket to bring back to show his ethereal flatmate.
As it happens, this strange jewel is in fact part of the Nanana Collection, and what's more he's actually snatched it from under the noses of those who were intending to steal it for their own ends. While those directly responsible are baffled by the disappearance of the jewel, Yama finds himself the subject of investigation by "master detective" Tensai Ikkyuu and her maid assistant Daruku Hoshino, who quickly not only deduces that it was he who found the jewel but also manages to embarrass him thoroughly in the process.
Although Ikkyuu's attempt to return the jewel to the police doesn't quite go to plan, she - alongside Daruku - nonetheless chooses to transfer not only into Yama's school but also his class. In fact, Yama seems to have a constant stream of oddballs taking an interest in him at present, as the president of the Adventure Club also makes his acquaintance with a view towards him joining. Given that the club relates closely to Nanana, her treasures and her eventual death, Juugo gives joining some serious thought - but first, he must pass a tricky initiation test, which is where our resident detective gets to strut her stuff.
For all of the pandering nonsense that this series throws at the viewer (why do we need two characters dressed as maids? Why is one of them a "trap"?), there's also rather a lot of fun to be had with this week's episode beneath the surface - it has some good comedy moments, Nanana is rather lovable as a laid-back lead female character, and there's already a good rapport amongst the show's growing cast. It doesn't feel like a noitaminA show in the slightest, but put that to one side and I found myself rather enjoying this episode of Nanana's Buried Treasure, which hopefully bodes well for it provided it keeps heading in the right direction.