Stella (Haley Lu Richardson
) has cystic fibrosis, which means she can't be touched by another human for fear of being exposed to bacteria, which could be fatal for her. She wears a mask in the company of others and has to keep a distance. She follows all of the rules she's been given because she doesn't want to die.
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.