Within a corrupt underworld city, a man and his master live their intertwined lives. Arwin, the Princess Knight, stands out like a pristine crimson bloom in the midst of decay. Matthew, a common adventurer, appears to be the lowest of the low, a feeble combatant and a craven spender on vices. Unbeknownst to all, he is dedicated to his princess knight, willing to soil his hands as needed for her protection.