An old friend of Hammer's, Ridge, has uncovered something big but didn't tell him what it was. When he is killed in a car bomb Hammer is determined to find the killer. A search of Ridge's office leads Hammer to a private detective convention when he finds out that Ridge used to take the pictures used in divorce cases. A list of names found in Ridge's office provides a clue, especially when the people on the list are being killed. Hammer manages to find the killer but still has to found out why.
—jem