The protagonist of the story is the Harlequin, alter ego of Everett C. Marm. He rebels against the system in this dystopian society, in which everything must run to the tightest of schedules. The Harlequin sets about challenging society's obsession with clock time, actively disrupting people's work schedules as a way of freeing them from their unhealthy fixation.
By the same token, the Harlequin's antagonist is the Ticktockman, a state functionary whose job it is to ensure that everyone strictly adheres to their schedules, on pain of having their lives shortened accordingly. (Time off for bad behavior, if you like.) Eventually, he puts an end to the Harlequin's playful transgressions by having him brainwashed. Yet ironically, this accomplishment entails the Ticktockman falling behind schedule himself. And that represents quite a victory for the Harlequin.