Nash and Joe are on the trail of a ruthless gang of thieves threatening to release the lethal nerve gas over downtown San Francisco unless the area is evacuated. Once the area is cleared of people, the criminals plan to move in and rob the banks in the area. Racing against time to capture the criminal mastermind behind this scheme, Nash is surprised to discover that the gang leader is Pamela Smith, a beautiful, brilliant chemist who created the deadly gas. Meanwhile, a mysterious woman appears who claims to be Joe's daughter from a college fertility experiment in which he participated years earlier.