Fly Me to the Moon, Vol. 21 (manga)

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 has 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.