Lady Tweedia, a duke's daughter, was ordered to tutor a certain girl in exchange for keeping her engagement.

Her name is Haru, the Saint summoned from another world.

It seems Crown Prince Jade intends to eventually make her his queen.

Learning this, Tweedia was enraged by the prince's utter selfishness.

(My engagement means nothing. But Haru—I won't give her to you.)

Thus, she devises a plan and resolves to raise her.

Into a splendid noble lady, just like Tweedia herself, whom the prince detests.