4400 overlooked, undervalued, or otherwise marginalized people who vanished without a trace over the last hundred years are all returned in an instant, having not aged a day and with no memory of what happened to them. As the government races to analyze the potential threat and contain the story, the 4400 themselves must grapple with the fact that they've been returned with a few "upgrades", and the increasing likelihood that they were all brought back now for a specific reason.

Based on the true story of the events that led to the death of Kenneth Chamberlain Sr., an elderly African American veteran with bipolar disorder, who was killed during a conflict with police officers who were dispatched to check on him.