Just when the guys think they're about to get away with a full shift with no calls, a call comes in for a car accident. When they arrive on the scene, a van has been flipped over and is barely balancing on the edge of a bridge, containing a young boy and father inside. The other car involved has gotten off relatively easy, and it's clear the driver is the cause of the accident when Casey notes alcohol on his breath and open containers in his car. The policeman on the scene notes it and agrees to take care of booking the driver. But when Casey returns after the father and son have been escorted to the hospital, he finds that the man responsible is nowhere to be found. Apparently, the driver is the son of one Detective Voight, a cop who has a lot of clout in Chicago. A man like Voight is one to make sure his son doesn't get mixed up in this kind of mess.