Now that Zenjirou’s adventurers on the Northern Continent have come to a close, he and Aura finally hear what made Lucretia so worried—secrets of the White Empire’s remnants and the hidden history of Utgard. Unable and unwilling to ignore the information—as questionable as it might be—the queen decides to send for the former king of the Twin Kingdoms. The meeting needs to be secret, though, and Margarita’s interest in Völundr is the perfect cover. Although Zenjirou has only just returned home, he soon finds himself heading out to the Twin Kingdoms to fetch the royals both publicly and clandestinely. Everything has started to unfold at once with gifts from the Four Dukes, lessons from his wife, and even communications from yet another country in the North. Zenjirou will have to navigate them all, even if it means any hope of regaining his ideal sponger life is all but lost.

This is the third volume in the saga of our beloved “sponging protagonist,” and at this point, “sponging” is the last thing he’s doing. A year has passed since his marriage to Queen Aura of Capua, and the capital has welcomed their new child and heir to the throne, Carlos Zenkichi. The kingdom is busy with festivities to celebrate the happy news, but something more ominous has reached Aura’s ears. Margrave Gaziel tells her that his territory has had no salt for a year, and with his lands lacking both sea and rock salt, it could spell the region’s end. While the queen immediately orders an investigation, Zenjirou’s free time is becoming more than he can handle in the inner palace, and he starts to investigate what advancements might be made to move their nation forward.

As a visitor to the royal court of the Twin Kingdoms, Zenjiro swiftly got caught up in the intrigue of a royal succession. Not all is as it seems, and even innocent gestures carry hidden meanings. To survive the dangers, Zenjiro has no choice but to design a brand-new magical item that will amaze the rich and powerful of this foreign realm. Any mistakes here could ripple all the way back home to Capua and change the fate of his whole family. It's time for Zenjiro to dust off his long-dormant skills in business and make a sales pitch fit for a king!

After a long journey, Zenjirou has finally arrived in Uppasala, Freya’s homeland. Immediately upon his arrival, he meets with King Gustav and various movers and shakers in the country. In order to finalize the trade deal between their countries, Zenjirou asks the king for his daughter’s hand. Naturally, many of those present are unwilling to give up their first princess—particularly to a prince consort—but the first prince, Eric, is especially hostile. His warrior spirit and aggressive personality lead him to absolutely refuse to allow someone who has not even passed the Rite of Age to marry his little sister. To attain the right to truly propose, Zenjirou finds himself facing a complex situation—one in which he will need to prove himself a man by the norms of a somewhat militaristic nation.

Yamai Zenjirou is your everyday office worker in modern Japan. One morning, he suddenly finds himself summoned to a tropical world where dinosaurs roam the land. He is told that this is the kingdom of Capua and the person who summoned him - its monarch, Queen Aura - wants him to marry her and leave his old life behind for a life of carefree extravagance as her prince consort. The reasons for her offer are many and varied, but she needs an heir, and she wants him to be the one to provide it! If he accepts, he’ll never have to work again, lazing around in luxury with no worries other than securing the kingdom its next monarch. Certainly, sleeping with the buxom beauty is far from a hardship, but is everything really as it seems? He’ll also need to give up everything he knows on Earth. Is he ready to drop it all at a moment’s notice for her sake? And how well will he be able to navigate the politics, people and culture of this new world if he does?

Two years have passed since Zenjiro was summoned to a kigdom in another world and married its beautiful queen. Now, Zenjiro and Queen Aura celebrate the birth of their child--the young First Prince of Capua---and the realm celebrates with them. Yet while Zenjiro is busy adjusting to his new life as a father, a bloody massacre breaks out along the vital Salt Road. A company of knights and warriors rides to do battle with all manner of wyverns, even as a delegation arrives from the Twin Kingdoms with an agenda all its own!