When a retired military man runs over a pedestrian, it's up to Lieutenant Joe Kenda to determine if the accident was the result of bad brakes or bad intent. A shooting in a dive bar leads to a quick arrest, but Kenda can't shake feelings of unease.

Beloved teacher Barbara Lewis is poisoned in her classroom; as doctors fight to save her life, Lt. Joe Kenda and his team delve into her personal affairs looking for clues, but the biggest revelation comes from the poison itself.