Returning for its fourth and final season, The 4400 explores the plight of the 4400 missing people who all at once mysteriously returned to Earth in a ball of light.
Even though the returnees had not aged physically, many of them reappeared with dramatic, paranormal abilities ranging from enhanced reflexes to precognition.
These extraordinary individuals are now monitored by a government agency called NTAC (National Threat Assessment Command).
In Season 4 of The 4400, widespread distribution of the drug Promicin has created a dangerous new world in which special abilities are no longer the exclusive province of the 4400.
The drug is distributed by Jordan Collier, who sees himself as the saviour of humanity.
Fifty percent of those who take the drug pay the price with their lives, while those who survive are ostracised by a government determined to rid the world of Promicin forever.
But Promicin distribution was only the first step...