After her engagement to the crown prince was called off, she was assigned to marry an unsociable duke.

"You're my wife, aren't you? You can't reject me."

Minerva is the daughter of a marquis and the crown prince's fiancee, but her engagement is suddenly called off one day. Shortly after that, though, she is assigned a new fiance: Duke Mars, the younger brother of the current king. His beauty and position are unrivaled, so any young lady would normally be delighted to marry him.
However, he's famous for being unsociable and hardly ever showing up at social occasions or even smiling in public. Minerva is unsure that she can be happy marrying him, but what Mars shows her during their bridal night is an incredibly sweet, devoted side of him, peppered with intense, possessive caresses!