After his classmate and crush is diagnosed with a pancreatic disease, an average high schooler sets out to make the most of her final days.

In an underground world where tunnels extend everywhere, even though they live in dark and confined spaces, people wear protective clothes and lead quiet and enjoyable lives. Patema, a princess…

At a high school full of unique characters, Tadano helps his shy and unsociable classmate Komi reach her goal of making friends with 100 people.