After punching a famous curator in the face for criticizing his work as "textbook and lifeless," Handa Seishuu is sent to Gotō Island to calm his nerves and find new inspiration for his calligraphy. Growing up in the city all his life, though, Handa must adapt to country life while meeting an assortment of quirky people during his tenure.

A high school student Yiyong, played by Tseng Jing-hua, gets into a bus accident that not only leaves him comatosed for more than a year, but also causes him to wake up with his grandfather’s supernatural powers. With that, Yiyong’s life will never be the same, and the original boring life of Yiyong becomes a fantasy-filled and wild monster-fighting adventure which he embarks on with the help of his school rival, Cao Guangyan played by Peng Cian You, and a rookie policewoman Chen Chuying played by Vivian Sung.

Set six years prior to the events of Barakamon, detailing the life of Seishuu Handa as a high school student—and a very interesting life it is. In Handa-kun, Seishuu Handa is admired by his peers as a calligraphy genius and given the utmost respect, but Handa-kun himself is under the mistaken impression that the deference and attention he receives from the other students is actually bullying. Handa just wants to live a quiet life, but hilarity ensues as one character after another challenges his position as the school idol, and somehow comes away as a fan all while Handa is horrified and clueless.

A proud young calligrapher is punished for punching a critic by being sent to a faraway island in the east coast of Japan. But as he meets and lives with the island's friendly people, his attitude begins to improve.