Usami-San Ha Kamawaretai!

Usami Nagisa is a yankee who suffers from a rare disease which causes her health to decline if she feels lonely. Sewa Natsuhito, the boy who sits next to her in class realizes this and keeps her company, but the only way Usami believes she can cure her illness is to make lots of friends, a process she might find harder and complex than she initially would have hoped.