A female knight is captured by barbarians and receives a marriage proposal from their heir. As she learns their customs, she questions her prejudices about their way of life

Reborn as Arthur Leywin after a mysterious demise, a former king retains his wisdom despite entering a new life as a baby on the magical continent of Dicathen. He masters magic, forging his path to rectify past mistakes.

One day while questing, he entered a dungeon and discovered a young girl being partially devoured by the weakest monster type - a slime.

When high school student Hitoyoshi meets his new maid, little does he know that the beautiful yet sullen woman has a dark history as an assassin.