Burdened with social anxiety, Keigo Sayama wears a face mask to school and avoids drawing any attention to himself unless absolutely necessary. However, when Keigo's stumble on the stairs puts him in close contact with the popular and outgoing Tsuzuru Saikawa, it is the start of a chain of events that might change his circumstances. As the pair spend more time together, Saikawa develops a fascination with the handsome face behind the mask, and he is willing to do whatever it takes to bring Sayama out of his shell.