Sometime after their triumph as the Phantom Thieves of Hearts, the group gathers at Cafe LeBlanc while preparing for graduation, their ordinary lives seemingly restored. Their calm is shattered when they are abruptly pulled into a bizarre alternate reality, a medieval European-style realm known as a Kingdom, ruled with an iron fist by the ruthless Tyrant Marie. With frightening ease, she overwhelms most of the thieves and bends them to her will through brainwashing. Just as Joker and Morgana are on the verge of falling to her power as well, they are saved by Erina, the fierce leader of a band of freedom fighters called the Rebel Corps. Vowing to help Erina overthrow the tyranny that grips this strange world, the remaining thieves join her cause and set out to spark a revolution.