Countdown is a propulsive action-thriller series created by Derek Haas, a veteran writer of network procedurals including the One Chicago and FBI franchises. Built for streaming momentum on Prime Video, the show trades on the ticking-clock urgency of its title while spinning out a sprawling conspiracy that keeps escalating across its thirteen-episode first season.

Jensen Ackles stars as Mark Meachum, a wisecracking LAPD officer who is recruited into a covert, multi-agency task force after a Department of Homeland Security agent is gunned down in broad daylight. What begins as a single shocking murder investigation soon reveals a far larger and more dangerous plot against the city, forcing the secretive team of operatives to race against time. Jessica Camacho, Eric Dane, Uli Latukefu, and Violett Beane co-star.

The series marks a high-profile reunion between Ackles and Prime Video following his fan-favorite run on The Boys, and it leans into large-scale Los Angeles location work and heavy stunt action to give the show a theatrical scale. Case-driven and fast-moving, Countdown was designed to hook binge viewers and deliver escalating stakes week over week.