After a 20 year absence, drifter George Walker returns home to settle his grandmother's estate. As if awakening from a long dream, he finds his childhood home condemned and littered with the remnants of squatters. In the midst of trying to save his past, George falls and strikes his head, triggering an onslaught of vivid nightmares and waking visions. As the horror intrudes on George's reality, his conviction grows that someone or something is trying to kill him.

Kay and Jay reunite to provide our best, last and only line of defense against a sinister seductress who levels the toughest challenge yet to the MIB's untarnished mission statement – protecting Earth from the scum of the universe. It's been four years since the alien-seeking agents averted an intergalactic disaster of epic proportions. Now it's a race against the clock as Jay must convince Kay – who not only has absolutely no memory of his time spent with the MIB, but is also the only living person left with the expertise to save the galaxy – to reunite with the MIB before the earth submits to ultimate destruction.