After escorting Prince Willie to the capital of Knightley, Ryo feels a weight lift off his shoulders. He's even managed to secure a position teaching the young prince how to use water magic. Life couldn't be better!

Before long, Ryo and Sera happily go on a sweets tour together. The two of them bond as they visit the other elves, but after they go their separate ways, a horde of monsters emerges from underneath the Temple! And then while he and Abel are trying to find the cause of this outbreak, an "island" falls from the sky and crashes right through the royal castle! As one crisis crops up after another, Sera struggles to protect her friends and is attacked by a powerful opponent.

"Do you really think I'll let you hurt the people I care about?!" Ryo will use his superhigh-pressure water currents to stave off a scheming enemy nation that has bared its fangs! The adventures of the strongest, freewheeling water magician continue in this frenetic fourth volume!