The 4400

A comet is due to pass by Earth, but its trajectory changes to a collision course, causing widespread panic. When the comet appears to slow down - as if it's coming in for a landing - 4,400 people are deposited in an explosion over Highland Beach.

The 4400 returnees have been missing from months to years. None have any memory of where they've been, none have aged, and a small number are beginning to manifest paranormal abilities. Tom Baldwin and Diana Skouris are appointed to investigate.

Tom and Diana are sent out to investigate a homicide that resembles the MO of a serial killer who was never caught nor heard of for 21 years. The first suspect is Oliver Knox, a member of the 4400.

The 4400 are attacked by a series of bombings after their names and addresses are leaked. Tom, Diana, and Dennis try to put an end to the bombings.

Tom is furious after finding out that Lytell has taken his son Kyle into custody. Diana offers to help him in getting Kyle back. Meanwhile, Richard suspects that Collier is trying to take control of Lily's life.