Overworked office employee Seiichirou Kondou would be fine spending the rest of his days in the same exhausting routine, but an unexpected act of heroism causes him to be sucked into a parallel world. His abductors, residents of the magic-filled Romany Kingdom, promise him a life of comfort as an apology for his accidental summoning. Unfazed, Kondou demands something that he thinks would suit him better: a job. After witnessing the incompetence of his new colleagues in the Royal Accounting Department, Kondou's workaholic instincts kick in, and he takes it upon himself to save the kingdom from complete bankruptcy. But this new world proves detrimental to Kondou. When the young and dashing captain of the Third Royal Order, Sir Aresh Indolark, saves Kondou's life, the two become something more than acquaintances. Though Kondou and Aresh initially struggle to convey their clashing values to each other, they slowly realize that this meeting will not only change their own lives but also the kingdom as a whole.

In sixth grade, childhood friends Yukiya Asagi and Miku Sakura created a game with the objective to embarrass the other person by taking turns saying I love you. Four years later, even as they are entering high school, the two are still trying to one-up the other and claim victory. However, as tender feelings begin to bloom in their hearts, the simple phrase has taken on new meaning beyond the rules of their game. With the passing of each day, the urge to become more than childhood friends grows—but both Yukiya and Miku resist making the first move, hesitant about what is in store once the game finally ends.

For centuries, the Poison Masters have perfected the art of assassination. Among them, the Gero family stands as one of the five most powerful families of Masters, wielding unmatched skill and influence. Hikaru Gero, heir to this infamous bloodline, has lived his life deep in the shadows of the underworld, far removed from love or marriage. However, to ensure the Poison Master bloodline does not die out, the head of the Gero family declares that Hikaru's sister will be forced to bear an heir. Soon after, Hikaru crosses paths with Mei Kinosaki, a brilliant marriage swindler who also happens to be his current assassination target. Determined to protect his sister and solve the succession problem himself, Hikaru makes an unexpected request on the spot—asking Mei to help him get married. ...That's the first time anyone's ever proposed like that. And so, with the cunning marriage swindler Mei as his advisor, the elite assassin Hikaru sets out on the toughest mission for love. His goal? The ultimate marriage. The most unlikely duo—an assassin and a marriage swindler—take on the world's toughest mission for love! (Source: Official site)

The story follows Koichi Asakura, a designer for an ad agency who works hard but receives no recognition. After being dropped from a project, he visits a place from his past, where he met Eren Yamagishi. Eren, meanwhile, is recognized as a genius left-handed graffiti artist in New York, while enduring the struggles that come from her own path in life. (Source: Crunchyroll)