A car bomb explodes, killing the Vice President of Sawchuck Industries. In their search for suspects, Chase and August meet Meredith Nowell, a beautiful young volunteer at Green Planet, an environmental protection league. Meredith reveals that Sawchuck Industries had been dumping deadly toxins, which infected Los Angeles groundwater, killing a mother and daughter. When another Sawchuck executive is killed in an explosion, the detectives begin to suspect Joshua Duncan, the man whose wife and daughter died of cancer as a result of the poisoned water.

Leonard Murdoch, a scientist for the high-tech firm Biotech, is murdered, and Chase and August suspect someone in his company wanted to keep him quiet. The detectives get a call from a Biotech whistleblower who tells them that the firm's CEO is planning to sell a top-secret biological chemical to international American enemies. Chase is convinced it's a cover-up for a government study of alien DNA, but before he and August can learn more, they are surrounded by military vehicles and men in black.

A motorcycle cop is shot and killed during a routine traffic stop. The killer's car is traced back to James Burquette, an attorney who had reported the car stolen earlier that day and is shocked to find that it was used in a cop slaying. When another officer is killed, August goes undercover as a motorcycle cop, hoping to lure the killer into striking again.