An LAPD officer joins a secret task force to investigate a suspicious murder, but uncovers a sinister plot that requires the team to unite and save millions in the city.

Countdown starts following a suspicious murder in broad daylight, which leads to LAPD officer Mark Meachum being recruited to join a secret task force of undercover agents from all branches of law enforcement to investigate. But as the truth of a more sinister plot comes into focus, the team must overcome their conflicting personal agendas to unite and save a city of millions.