"My final place is an enemy country ..." Ilsa, who was born as an imperial aristocrat, loses her family in a war one day. She has lost her territorial rights and she has no choice but to go to a military battleship as a maiden, where she encounters an attack on the enemy, the Commonwealth. She escapes and Ilsa falls into the sea, but when she wakes up she becomes a federal prisoner ... She is Ilsa who was taken as a slave to the hero Sigwald, who is called "Ichi no Senshi (Einherjar)". She thought she would be treated badly ...? Is this encounter fateful?