Theodosine, a marquess's daughter who was dumped by a cheating crown prince, is forced to marry a weird duke in the frontier who is only known for bad rumors. The duke she meets is exactly the weirdo from the rumors, wearing a horse mask……but beneath the horse head is a stunningly beautiful young man!? "You're over 30, right? Why are you tearing up so cutely?" Furthermore, the duke is a high-spec magic-wielding knight—something you could never imagine from his appearance——!? A romantic comedy between a dead-serious young lady who knows nothing of love and a reclusive duke with a hidden past!