Kamiku Kyotaro, a disciplined high school student skilled in Japanese fencing, experiences a sudden transport to a new realm. Tasked by the Trekwards Kingdom due to their queen's enigmatic illness, Kyotaro, amidst a society where women hold power, is enlisted into the royal harem. His duty? To sire an heiress by engaging intimately with the five princesses, tackling a precarious predicament to safeguard the kingdom's future.