Wesley Gibson is a disenchanted everyman, slogging through life with a dead-end job and a cheating girlfriend, plagued by panic attacks and a sense of worthlessness. His mundane world is turned upside down when he is suddenly attacked in a store by a mysterious assassin. Wesley is rescued by Fox, a member of the Fraternity, a secret society of assassins that his recently murdered father was part of. She reveals to Wesley that his long-lost father was one of the world's greatest assassins, and that he has inherited his exceptional killing abilities. Surprised and intrigued, Wesley is drawn into the Fraternity.

Under the tutelage of Fox and the Fraternity's enigmatic leader, Sloan, Wesley begins to train in the art of assassination, developing lightning-fast reflexes and incredible combat skills. He learns about the Fraternity's ancient textile loom that weaves fate itself, giving names of targets through a binary code hidden in the fabric. As Wesley becomes more ingrained in the Fraternity's world, he starts to transform from a nobody into a powerful assassin, embracing his new-found purpose with each mission. He must navigate the perilous waters of loyalty and betrayal, all the while questioning the morality of his new lifestyle and the true intentions of his new allies.