When an officer with the Department of Homeland Security is murdered in broad daylight, LAPD detective Mark Meachum is recruited to a secret task force, alongside undercover agents from all branches of law enforcement, to investigate. But the hunt for the killer soon uncovers a plot far more sinister than anyone could have imagined, kicking off a race against time to save a city of millions.

Countdown ran for 1 season. No new episodes are scheduled.