Four misfits find themselves struggling with ordinary problems when they are suddenly pulled through a mysterious portal into the Overworld: a bizarre, cubic wonderland that thrives on imagination. To get back home, they'll have to master this world while embarking on a magical quest with an unexpected, expert crafter, Steve.

Shouya Ishida starts bullying the new girl in class, Shouko Nishimiya, because she is deaf. But as the teasing continues, the rest of the class starts to turn on Shouya for his lack of compassion. When they leave elementary school, Shouko and Shouya do not speak to each other again... until an older, wiser Shouya, tormented by his past behaviour, decides he must see Shouko once more. He wants to atone for his sins, but is it already too late...?