When Inspectors Delaney and Claiborne arrive at the scene of a mass shooting on Fisherman's Wharf, they're not only stunned by the carnage, but at the bizarre way in which the shooter took his own life. The medical examiner soon announces the cause to be a one-in-a-million brain lesion. Case closed. Two days later, another strange crime takes place when a schoolteacher stages a brazen smash and grab at a jewelry store. Even stranger is the discovery that the teacher has the same brain lesion. Soon, Dennis and Clay are confronted by a never-ending crime wave committed by first-time offenders. The detectives must rewrite the rule book if they're going to crack the case and unmask the criminal masterminds who threaten to bring San Francisco to its knees.