Stella (Haley Lu Richardson) has cystic fibrosis, which means she can't be exposed to other cystic fibrosis patients, for fear of cross infection. She often wears a mask to avoid germs and follows all of the rules she's been given because she wants to live.

When she meets Will (Cole Sprouse), another cystic fibrosis patient, she's immediately drawn to him, because he's a rebel who doesn't seem to care about the rules they've been given. Although he has a devil-may-care attitude about the length of his life, when he develops feelings for Stella, he realizes his actions may affect her.