Tachibana Hinata and Jinguuji Tsukasa have been best friends since childhood. Now, at 32 years old, they're both average businessmen. One night after a mixer, an entity calling itself a goddess sends them to another world. When Jinguuji opens his eyes, he sees Tachibana, who's been transformed into a beautiful, blue-eyed, blonde girl. Now that the two are of different genders from each other, they're each bewildered by the other's charms. They steel their determination to defeat the Demon Lord in order to return to who they were with their relationship still intact.

After being sent to another world, Tachibana and Jinguuji spot a small settlement at the edge of a forest. However, unbeknownst to them, the settlement is under attack by bandits. Tachibana goes in to the village alone to gather information on the world, but Tachibana's "Unparalleled Beauty" skill, which grants the ability to cause the status effect "Charmed," instigates a falling out among the bandits...

Continuing on their adventure, Tachibana and Jinguuji arrive in a large town with a market and rows of buildings. But Tachibana's "Unparalleled Beauty" Charms men, one after another, leading Jinguuji to resort to purchasing a certain item. At the same time, a dark swordsman reacts to seeing Jinguuji's wearing a suit, and challenges Jinguuji to a fight. Then Tachibana and Jinguuji learn that the swordsman is actually their fellow countryman...?!

In order to prove that he is a true hero who has been summoned by a goddess, Schwartz, a high school student who is from Japan just like Tachibana and Jinguuji, has takes on a mission to defeat the living armor which has been attacking tradesmen near the Mercs territory. The living armor only targets magic items, and tries to take Schwartz's holy sword, Gram, and Tachibana's tiara, but...!

The Goddess of Night, called down by Schwartz's skill, explains the mystery behind Jinguuji's arrival in this world. Tachibana and Jinguuji leave the Mercs territory, heading for the royal capital. Along the way, they stop by a peculiar village where squid is adored. There, as part of the preparations for a strange ceremony, Tachibana is kidnapped as a sacrifice...?!