In a dystopian future, following a devastating Third World War, the totalitarian state of Libria has risen with the goal of suppressing emotions to prevent conflict, using the drug Prozium to numb the population's feelings. The government's enforcement arm, the Grammaton Clerics, is tasked with destroying anything that might stimulate emotion, including art, literature, and music. Among these clerics is John Preston, a high-ranking official renowned for his ruthlessness in eradicating those who resist the regime, known as "Sense Offenders." Preston's unwavering commitment to the cause begins to falter after he accidentally misses a dose of Prozium, leading him to experience sensations he has suppressed for years.

As Preston struggles with his awakening emotions, he becomes increasingly torn between his duties and his newfound sensitivity to the world around him. His internal conflict escalates when he partners with a new cleric, Brandt—a rising star in the ranks—who admires Preston's legendary status but is also eager to expose any sign of transgression. Meanwhile, Preston's interactions with Mary O'Brien, a detainee with a deep connection to the resistance movement, complicate his loyalty. Faced with growing compassion and empathy, Preston must decide whether to continue to uphold the oppressive order or risk everything to rebel against the very system he has tirelessly enforced.