As the show gets out of the way very quickly, Zac was your normal run of the mill kid interested in math, girls, and college. All of that went away when he was diagnosed with cancer at 17. We catch up with him while he is in isolation after treatment and very bored and very terrified. While there he meets headstrong Mia who has checked in for chemo for cancer that is supposed to be 80% curable. Mia is just going to get this over with and then back to her popular girl life... but things don't turn out like she thinks they will.
The actors here are strong and I buy their growing love in a desperate place. The story is not afraid to go for the unhappy ending (perhaps this is from the book) and that only helps bring meaning to their growing relationship.
My only problem with the show was that it was super unrealistic. Both actors looked like they could jump out of bed and on to a fashion show the entire time. the hospital rooms were massive and lit in the most romantic way possible. Finally Zac and Mia do a lot of talking via thin walls. And I find that hard to believe in a hospital. But if you can let that go - this is a strong show.