Grace and Jimmy investigate an old shooting range and he tells her about the missing money. Meanwhile, Mitch helps Grace gain entry into Santa Rita and Tom and Evie are told to move out for a few days.moreless
A series of mysterious murders in which victims have been drained of endocrine fluid lead Keira and Carlos back to Liber8, as they attempt to save their leader, Travis. Meanwhile, Liber8 member Kellog delivers Keira a gift in an attempt to make truce, a gift that puts hers and Carlos' lives in danger, and could result in Kellog's expulsion from the terrorists' group.moreless
The translucent shapeshifters return to plague Fringe division, and a former Massive Dynamic scientist is involved. Meanwhile, Walter meets with Nina Sharp.
Sam abandons Dean to investigate a case from his childhood that he thought he had solved: a demon that kills criminals and eats their brains.
The Leviathan possession of Castiel has devastating consequences which leads Sam, Dean, and Bobby back to Sioux Falls, Meanwhile, Sam puts himself and Dean in danger as he begins to crack under intense pressure from Lucifer's mind games.moreless
The 4400 are attacked by a series of bombings after Barbara Yates makes their names and addresses known to the public. Tom, Diana and Dennis try to put an end to the bombings, while at the same time Tom is coping with Kyle's erratic behaviour.
Warren Lytell, an agent from Washington is sent to "monitor" the team's progress on the 4400 investigations. Jordan Collier offers protection to members of the 4400, while Richard and Lily begin to question his motives.
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 returnees — "the 4400" — 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, two Homeland Security agents, are appointed to find out what happened to the 4400.