When Stephanie goes missing, the FBI quickly find out that she used to be Stephen, a married man with two kids who underwent surgery for gender reassignment several years ago.
It's handled very well - there is a good balance of showing the difficulties people in her situation face, the prejudice of others and the fact that there are people from all walks of life who are actually very sensitive and accepting.
The main thrust of the story is very poignant. An initial sighting of her handing over money to a guy who seemed to be threatening her is a red herring. There are other miscues as well - could her brother have killed her? He's not pleased when she turns up.
But the real reason for her disappearance is worse - but at least there is a kind of happy ending to the whole thing.
Except for the fact that Vivian is then found lying on the ground having had an attack of some kind...