Tanta is a high school student with a weak personality. He's always getting bullied and picked on by the other kids. His father is too harsh on him, and the only person who made Tanta feel happy was his older brother.

Until his brother disappeared a month ago.

Tanta now wanders through life, becoming increasingly more depressed, uninterested in the kendo classes his father makes him take, or the legends of his ancestors, who supposedly fought against dragons. Tanta's life is heading nowhere, and the only person who cared about him is gone.

Then Tanta disappears as well.

Now in a mysterious new world with beasts and dangers previously unimaginable, Tanta's upsetting school life seems like a paradise by comparison. How did Tanta get to this dangerous world, and can he survive? Could this be the same place his brother disappeared to?

This is the world of Dragonex!