Joseon Crown Prince Lee Gang (Kang Tae Oh) is known by many as an unserious, pleasure-seeking man, but he uses this facade to mask his deep pain from losing his beloved wife. While his mother tries to find him a new spouse, he's dismissive of her attempts, only wishing to pursue revenge. His life takes a turn when he runs into Park Dal I (Kim Se Jeong), a merchant with amnesia who bears a startling resemblance to his wife. Although Dal I and Lee Gang's first meeting goes poorly, they soon find themselves as unlikely allies helping those in need. However, the two awaken one morning to the shock of a lifetime: they've swapped bodies. As Lee Gang and Dal I try to figure out how this happened, they uncover political conspiracies and dangerous secrets – and that their connection might run deeper than they think.