The 4400 are attacked by a series of fire-bombings after Barbara Yates made their names and addresses known to the public. Tom, Diana, and Ryland try to put an end to the bombings at the same time as Tom tries to deal with the disturbing behavior of Kyle, and Diana tries real hard to be a good substitute mother to Maia. However, the arrival of a Homeland Security agent from Washington, Warren Lyttel, makes their work even harder. Jordan Collier tries to provide his followers with safe shelter, but Richard and Lily begin to question his intentions as the bombings intensify.
The 4400 tells the stories of 4,400 people who disappeared over a period of fifty years and who all reappear at the exact same time without any memory of where they've been and what happened to them. Some of them have been altered and have strange abilities, both good and bad.
The series kicks off with a ball of light sailing toward Earth, but rather than the expected catastrophic event, thousands of people emerge from the ball of light. The returnees have been missing from a few years to several decades and no one has aged a day.