Three mismatched NCR troopers are sent to hold Outpost 37, a shallow trench nicknamed The Tooth, against a coming Legion offensive along the Colorado River. Corporal Valerie, a defector from the sterile order of Vault City, commands Private Kael, a tribal warrior whose family was slaughtered by the Legion, and Private First Class Junior, a terrified conscript from the scrapyards of Junktown. Sent as little more than bait to buy the main camp a few extra minutes, the three of them face wave after wave of Legion assault with dwindling ammunition and no promise of rescue. What begins as a forced, hostile alliance becomes something closer to family as they bleed, break, and hold the line together — and the medals waiting for them afterward turn out to cost more than any of them expected.