This is the kingdom of Fazan.
During a party at the royal castle, the First Prince declares to his fiance:
“Millia: regrettably, I am breaking my engagement with you.”
And the moment before Lady Millia, the Prince’s Fiance, was about to be sentenced to deportation…
The body of the First Prince’s paramour was discovered!
Lady Millia, whose engagement was just broken, was suspected of being the murderer, however…
She was a detective in her previous life?!!
And so she challenges the mystery to prove her innocence.