Jiyoung Kim was an ordinary 23-year-old office man. Work, go home, sleep, repeat. Tired of the repetitive life and exhausted beyond repair he stands at the edge of the roof of his workplace. So tired. Where was his adventure? He wanted to end it all, of course, he didn't have the guts to do it. And yet somehow he wakes up in a body that is not his own. Prince Cassius, the middle child of 5 and the illegitimate child of Emperor Kronus and his unknown mistress. Cassius was going to be the future tyrant, how do we know this? Well, Cassius was the villain of a novel that Jiyoung had read, 'The Throne Is Poison'. Now Jiyoung has to survive his new life and change the path of becoming a tyrant.