Nix is confused because she has been following Zoe for a while now but she hasn't died yet when she was supposed to.
Nix decides to befriend Zoe because she wants to work out why she isn't dying
Zoe's brother is very controlling of her and he makes her scared and vulnerable
Nix is about to cause the accident that will kill Zoe but Zoe explains to her that she knows what Nix is doing and will happily pass over to the afterlife with Nix because she wants to get away from her brother
Zoe and Nix are in the afterlife but Zoe can change between being alive and dead. They become very close friends and are almost inseparable.
Zoe decides that she prefers being alive because she doesn't feel so trapped. They decide that it will only work if they forget about eachother completely and they go their separate ways.