Sovereign Union Act

They spent their whole lives trying to beat each other until the Crown used the Sovereign Union Act to make them marry.

Short summary:
Five years ago, the Crown introduced the Sovereign Union Act, selecting twelve arranged marriages each year in an attempt to restore unity among Britain's increasingly divided ton.
This year's selection is different. Every candidate belongs to the ton's younger generation-and among the twelve matches are Colin Bridgerton and Penelope Featherington.
Childhood rivals, university classmates, and products of opposing ideals, they have spent most of their lives competing. Colin comes from the outspoken Modernist Bridgertons. Penelope belongs to the fiercely Traditionalist Featheringtons.
Now, during their final semester of university, they are expected to finish their degrees while navigating a public engagement, two feuding families, and a marriage neither of them chose.
They disagree about tradition. About duty. About the Crown. About each other.
Unfortunately, the Sovereign Union Act does not require them to agree.
Only to marry.
And falling in love was never part of the arrangement.