Oji No Yume to Kagi No Ohi (Links Romance)

[Machine Translation] A businessman who grew up in an orphanage and has been alone in his whole life, Sudo Silica has been having the same dream ever since he was a child. In those dreams, the same precious childhood friend has always been there for him. On her way home, a handsome man with black hair and blue eyes, who calls himself Wilfried, suddenly appears and takes her to another world. He tells her that she is the missing key to the world and that she is to become the next queen of King Wilfried. However, unable to take in the situation, she adamantly refuses, but is informed that she had promised to marry him in the past...

天涯孤独で施設育ちのサラリーマンの須東珪は、子供の頃からずっと同じ夢を見続けてきている。その夢の中ではいつも同じ大切な幼馴染みが寄り添ってくれていた。今日も同じ夢を見て目覚め、一日会社で働いて帰る何気ない一日だったが、帰り道に突然ヴィルフリートと名乗る、黒髪碧眼の美形な男が現れ、異世界へと連れていかれてしまう。その世界で珪は行方不明となっていた鍵と呼ばれる存在で、次期国王・ヴィルフリートの妃になるのだと告げられる。しかし、状況が飲み込めない珪はそれを断固として拒否するが、過去に結婚すると約束していると知らされて...。