After helping handle the mayhem in the royal capital, Ryo finally returns to Lune. Back home, he accepts a job with the members of Room 10 in the coffee-growing haven of Kona! As he and his friends solve the village's problems and savor its delicious food, he learns something wildly unexpected-his best friend and partner in crime, Abel, is the second prince of the Kingdom of Knightley.

While Ryo is still processing what he initially brushed off as a joke, the Handalieu Federation declares war on the neighboring Principality of Inverey! To make matters worse, his beloved disciples are kidnapped after being embroiled in the war...

If his enemies think they can disturb his peace, they have another thing coming! They'll be trembling in fear when Ryo shows them what his water magic can really do. And when he joins forces with Prince Abel, their enemies won't know what hit them! The adventures of the strongest, freewheeling water magician continue in this frenetic fifth volume!