Isabelle's son goes missing and she will stop at nothing until she finds him. 

This one pulled me right. We follow Isabelle, an mother whose son is missing, she is grieving, suffering from PTSD, and barely sleeping. She is the definition of an unreliable narrator, yet you want to believe her. We are steeped in her grief and paranoia. You are right with her the entire time picking apart the pieces and trying to make sense of it all. 

There are definitely a few red herrings along the way. Did she do something to him while sleep walking? Was it her narcissistic husband? Is Whalen the guilty one? Was it the creepy man down the street? What are the cops hiding? 

We find out that when she was younger, Isabelle had a history of sleep walking. One night her sister died in the marshes behind the house.

We are lead to think that  Isabelle lead her to her death and that she killed her son while sleep walking. Then we find out that it was actually her mother, suffering from severe PPD who was guilty. She has planned to kill herself and her 2 daughters, but only the one daughter died.

The whole time I thought it was the husband.

He is obviously a narcissist, possibly sociopath who is manipulative, controlling, and gaslights everyone. He is always on the hunt for a younger version of his wife. His first wife died of suicide while pregnant and then his son with his second wife goes missing while he is in the throws of an affair with a younger model. Convenient or guilty? Well he is certainly guilty of something, but not of killing his son.

I was shocked when

it was revealed that it was the girlfriend who kidnapped her son! I was not expecting that at all. She was jealous and wanted Isabelle out of the picture, so she took the child and gave him to a woman to raise.