Fraser's next task is to escort a Canadian Diplomat's daughter to a ball, meanwhile, Ray is trying to track down a murdered mobster's contact list which has been stolen by a mysterious woman (guest star Stacy Haiduk).
While in pursuit of fleeing diamond thieves, Fraser is thrown from the back of the van and is so badly concussed that he loses his memory.
With no other witnesses and the hostage in jeopardy, Ray must race to help get Fraser his memory back and recall the van's licence plate number, by seeing if anything familiar speeds up his recovery.
As the pair become involved in ensuring his safety when someone attempts to kill the witness, Fraser begins having doubts about the nature of the case as evidence on each robber narrows down who is the assassin.
Fraser and Kowalski begin a murder investigation that leads them on a Great Lakes freighter.