Lockdown is a map that takes place deep in the Amazon jungle where Horizon has a secret bio-weapons testing facility. When your squad shows up, you realize that there has been an outbreak of specimens and that your job is to clean up the mess. A local Response team got to the location before you and they had the floor swept with them. Air Support surrounds the facility, mopping up any escaping/escaped specimens.

The level also has a "Lockdown" mode (hence the map name) that goes into effect at certain times, the first time at 14 mins into the game. When lockdown activates, you'll notice red flashing lights where doors are closing. Once closed, zombies won't attack the doors unless you weld them. This gives you a chance to catch your breath for less than 2 minutes and take free shots at zombies out the windows. Once the doors start opening, it makes killing zombies outside your doors easy works as the doors open slowly. The map doesn't go into lockdown very often, evening the playing filed for the zombies.