The game's story (narrated by Peter Jason) follows the exploits of Jericho Cross, an outlaw-turned-vampire, and his employment in an ancient vampire-hunting order known as the Darkwatch.
After unwittingly releasing the Darkwatch's greatest enemy, a vampire lord named Lazarus Malkoth, Jericho is conscripted into the Darkwatch as an elite operative. Jericho, however, is slowly turning into a vampire himself, after being bitten by Lazarus. The game outlines either Jericho's struggle for humanity or his descent into darkness, depending on the player's actions. The game begins in Arizona Territory in 1876 with Jericho attempting to rob a Darkwatch train that is transporting the captured Lazarus Malkoth to the Darkwatch Citadel, a frequently mentioned and often visited location in the game, and in doing so releases Lazarus into the West. In a seeming bit of mercy, Lazarus bites Jericho and gives him the curse of the vampire, causing him to slowly turn into one. The game continues with the introduction of Cassidy as well as the appearance of Shadow, Jericho's undead horse. As the game progresses, Jericho finally makes his way to the Darkwatch Citadel, where he meets General Clay Cartwright, the current leader of the order. Cartwright puts him through Torture Maze, the Darkwatch initiation exercise which was designed as a test for Darkwatch Regulators, but Jericho gets a special version specially designed by Cartwright to kill him.
When Jericho passes the test anyway, he begins to do missions for the Darkwatch. Missions include tasks ranging from fixing some of the damage he has caused to acquiring Darkwatch equipment, such as the Darklight Prism, a stone that allows vampires within its vicinity to use their powers and walk in sunlight.
