The film is based on the graphic novel series, which was created by author Greg Rucka and illustrator Leandro Fernández. Here’s the synopsis:
Guard tells of a small group of soldiers, led by a woman named Andy (Theron), who are inexplicably immortal and have been working as mercenaries through the ages. The novelty of not dying long gone, the group gets a jolt in their bones when they discover the existence of a new Greg Ruckimmortal at the same time as a nefarious organization captures their undying actions on camera.
The cast also includes Harry Melling (The Ballad of Buster Scruggs