The story takes place in a fantasy world consisting of humans, Dragonoids and Monsters. There is a relative harmony between the three races. There are also Drops, spherical objects that come out of the planet, which can power up the Monsters. Humans and Dragonoids can take on the role of Dragon Callers if they have the capability to see the Drops, wherein, they form bonds with monsters. Currently, the planet is facing Drop Impacts, occurrences where a large amount of Drops are suddenly generated in a single area (and can also spread), which affects the lands and makes the Monsters berserk. In fact, one of the main duties of Dragon Callers is to settle the Drop Impacts by stabilizing the Drop distribution.
In this story, the world is in chaos, thanks to Washu. Now in order to save it, Tenchi Masaki must go undercover as a student teacher at an all-girls school. Unfortunately for him, trouble always comes his way as he has a hard time dealing with the hijinks of his new students.
In the Sun Kingdom, sunshine is part of its citizens' everyday lives, and rain is something that they have never even heard of. However, in a faraway land called the Rain Dukedom, the weather is reversed, and everybody has the power to create rain with their voices. Livius Ifrikia has conquered the entire world and expanded the Sun Kingdom's influence in the three short years since he was crowned king. Upon learning about the powers to create rain, Livius decides to marry Nike Remercier, one of the princesses of the Rain Dukedom. However, those outside the Sun Kingdom have spread a rumor that Livius is a cruel, ruthless, and tyrannical ruler, and as word reaches the princess, she begins to prepare herself for the worst. But when she finally meets her fiancé, Nike discovers that he is an entirely different person from what she originally expected.