The theme is dams.Shoon and Keito were out for location, and they checked out some dams with a pretty guide named Ryu. He looks like an idol !
I love the part where Shoon and Keito were holding hands, and when Keito lost a true or false game, he had to give Shoon a piggyback! I think that they're the cutest pairing on Hyakushiki, especially since I get the feeling that Keito can be himself in front of Shoon.Notice that when Shoon jumps on Keito's back, he calls himself for "Shoko",Japanese girl names often end with -ko)
Then Shoon asked Keito to show his manly side, so Keito run up stairpath and made Shoon really scared. He screamed like a girl, kawaii!

Credit for the raw video goes to Irea.