Spenser is hired to protect a woman who is being targeted by a professional assassin.
He is been hired by the sister of the woman he is meant to protect.
Luckily the first hit goes wrong but when he finds the weapon. Hawk tells Spenser that this is major league firepower. Someone big wants the woman dead and Hawk would only works with Spenser if he gets paid upfront.
It gets worse as Spenser finds out that the woman that hired him and the woman he is protecting is the same person. She has a split personality and a past with the security services.
There is some information she has that people will kill for.
Once again Hawk is there for Spenser at the right time. This time Spenser has to get Hawk out of police custody after tanglin with the assassin and his specialist gun supplier.
Hawk also has connections with top level politicians. He just knows that there is a weak link in the security services and someone is dirty.
The story has Spenser tangling with espionage and psychiatry.