Hood is called in when autistic children begin to be abducted, only to reappear apparently on the road to recovery. But when one dies, solving the mystery of where the children go lies in the head of one of the abductees, and she may be the only lead to saving the latest kidnapped child.
The appearance of frozen bodies on sunny California days puts Hood on the trail of a chemical compound, and a madman determined to stop what he sees as a perversion.
Hood is called in to clean up a mess at a secret government project, but when it turns out the study subjects are not what they're supposed to be, the race is on to prevent any more deaths.
Dr. Jacob investigates an epidemic of violent outbursts by usually law-abiding citizens in a small Texas community but then exhibits to the same erratic behavior.
Water purported to cure cancer puts Hood and Rachel searching for a scientific explanation, but the answer is more deadly than the diseases it's supposed to be curing.
Gepetto resurfaces with the discovery of identical quadruplets from different mothers, leaving Hood and Rachel scrambling for clues to identify her, and the hit man she's hired, before another murder occurs.
A case of mercury poisoning that could turn into an epidemic puts Hood, Young and an eager field agent to work tracing the source of the mercury, but as every lead becomes a dead end they must begin looking for an unnatural cause.
Hood is called in when people in Philadelphia begin falling victim to an unknown poison that affects the nervous system and causes one to become a fireball.
Hood goes up against an FBI deputy director when a psychotic woman accuses the man of stealing her son, and the stakes go much higher when Rachel is taken hostage and Jacob is accused of complicity in the crime.