FBI agent Audrey Parker arrives in the small town of Haven, Maine to solve a murder and soon discovers the town's many secrets—which also hold the key to unlocking the mysteries of her lost past.

Al Shines, former king of the US race car track circuit, has a hard time starting his own team, once he's fired by his sponsor Robin Cates. Robin hired Al's immature daughter Kylie Shines instead. She resents Al's inevitable 'absence' as a widowed father, as well as the reigning champion, equally young but professionally vetted Kid Walker. Kylie tries to prove herself against Kid while having an on-off affair with him. Cates's marketing strategy dictates his intentions to manipulate Walker and both Shines racers.

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.