4400 centers on the return of 4400 people who, previously presumed dead or reported missing, reappear on Earth. Though they have not aged physically, some of them seem to have deeper alterations ranging from superhuman strength to an unexplained healing touch. A government agency is formed to track the 4400 people after one of them commits a murder.

Eighteen years after the murder of her parents, Sara Tobias searches for the meaning of the numbers '11:11' that was scratched in blood beside her mother's body. Following three sudden murders, supernatural events are unleashed as she gets closer to the truth.

Boston cop Pally is forced into early retirement, putting a strain on his marriage. Pally's stepbrother, Ray, attempts to lift his spirits by tipping him off to a sure-bet racehorse. But their attempts to secure the champion equine are thwarted by a local mob boss, who steals the horse as repayment for a gambling debt. With their investment on the line, Pally and Ray become entangled in a web of underworld crime and murder.

A group of snowbound strangers discover there are killers amongst them.

Duncan MacLeod cannot die -- he is a 400-year-old immortal, who has seen his share of humanity's history. Still, he risks his life in battle against other immortals and tries to save people from harm.