What's the point of having a new heart if all it does is break?
Early 40's mum Lara is recently divorced - collatoral damage from the 'much younger girlfriend mid-life crisis' syndrome. She moved from London to Cornwall and needs to get her own life back - to start again. That's not easy for a 40-something, and even less easy with a teenage daughter with 'baggage'.
Her daughter, Gussie, is 15-years old; she's on the verge of becoming a woman - if she lives that long.
Gussie has heart disease and has been ill since she was born. She's had three life-saving operations already, but her heart can't take it any more. She is waiting for a transplant. If she doesn't get one soon she'll die.
The Story

Lara gives Gussie as much life as possible; but how much life can you cram into a small space just in case it doesn't last? And what sort of life do you choose?
Lara is also re-forming her own life. It's difficult after years of marriage; there's a lot to re-learn. Dating is difficult when she can't be reliable. Gussie always comes first - even if it means cancelling at after the last minute.
The doctors have decided that Gussie is a 'priority case'. This means when the right heart arrives Gussie will need to be well enough for the operation - no colds, temperature or anything else that most people would shrug off with an over-the-counter remedy. She has to be looked after - closely.
Now, nearly a teenager, Gussie is beginning to demand and exercise her independence. She doesn't want to be told what she should or shouldn't do; and she certainly doesn't want to be fussed over. She wants to be 'normal'.