Over the last century at least, four thousand four hundred people who were overlooked, undervalued, or otherwise marginalized vanished without a trace off the face of the planet. Last night, inexplicably, they were all returned in an instant to Detroit, MI, having not aged a day and with no memory of what happened to them. As the government races to understand the phenomenon, analyze the potential threat, and contain the story, an empathetic social worker and hardened community corrections officer are among the civil servants called upon to deal with the uncanny refugees. The new partners clash in ideology and approach, but gradually find they have more in common than they thought as they become familiar with those under their care, including: a lawyer and resilient young mother from the early aughts, whose unexpected reunion with her estranged husband and suddenly teenaged daughter is immediately rocky; a WWI Army surgeon fresh from the Harlem Renaissance; an influential hidden figure from the Mississippi civil rights movement; a black sheep reverend-scion born to a notable televangelist family in 1990s Chicago; a seemingly shallow but misunderstood D-list reality TV star from Miami, circa 2015; and two wildly different unaccompanied teens, a vibrant girl whose bell bottoms give away her 1970s upbringing, and an introspective, prescient boy whose origin remains a mystery. These unwilling time travelers, collectively the 4400, must grapple with their impossible new reality, the fact that they've been returned with a few... upgrades, and the increasing likelihood that they were brought back now for a reason they're only beginning to understand.