A man, obviously involved in some criminal enterprise with his two accomplices, seems very ill. After he leaves, one of the accomplices makes a crack about the guy being a dead duck.
The sick man then gets in his car but can't get far before he pulls over. He calls to a man on the corner to drive him to the airport for one hundred dollars. This messes up the accomplice's plan, and he follows the pair and runs them off the road. The passenger - the original ill man - dies. The driver lives and is being charged with vehicular manslaughter and with possession, since the ill passenger slipped some drugs into the driver's pocket before the car crashed.
Sam is doing the post mortem and finds that the dead man in the car died because of bleeding from a gash in his head because his blood would not clot. Quincy gets involved and finds that the man would have died with or without the accident due to exposure to high levels of radiation. The man worked in a nuclear facility, but he was not exposed to the kind of radiation that is found in such a plant.
So with the audience knowing the who and not the how or the why, and Quincy knowing not even that, it is very interesting to watch Quincy work out exactly how and where the man was killed and by who.
I'd give this episode higher marks, if not for the histrionics displayed by the wife of the man being held unjustly for the murder of "nuclear man". Quincy is just trying to help - in fact he's meddling and jeopardizing his job to prove the guy being held is not the killer - and yet the suspect's wife keeps coming into his office to yell at him for not doing more!