 When Mac and DiMaggio go to meet a police informant at a waterfront setting (Mac complains that DiMaggio s car is not only cramped, but "has the baldest tires I ve ever seen"), the informant s car suddenly starts up and nearly runs them down before plunging into the ocean. The informant is found later slumped in the driver s seat, with an empty suitcase beside him. It looks like he died from the impact, but Mac isn t sure and orders an investigation. Meanwhile, a suave "businessman" named Phillip shows up and starts following Mac around, inviting him and his girlfriend to dinner and gradually insinuating himself into their lives to the point where he becomes a stalker. Police records indicate that Phillip is a hired killer who s never been arrested, because he uses extremely creative ways to kill and set up alibis for himself. Phillip soon confirms that Mac is his target. Mac can do nothing to arrest him and gets increasingly agitated, which is just what Phillip wants -- he plans to kill Mac "in self-defense" when Mac loses his temper one time too many. Meanwhile, Mac is still investigating the murder of the informant, getting involved in a nasty real-estate dispute, and trying to find out who hired Phillip.