In the mountains, Tsukasa and Nasa find a final gift' and a final puzzle' left for them by Tokiko. Can Nasa unlock the high-tech secrets hidden in an antique clock? Or will Tsukasa manage to break things beyond repair? It's high time the couple finally had a talk with Kaguya, the girl genius who acts like she's new to this planet. Not that she'll do anything but drive Tsukasa up the wall.