For the past year, Silas Mason and Dominic Frey have been meeting every Wednesday. Frey needs to be dominated sexually; Mason wasn't previously inclined to that kink but liked the idea of having a chance to abuse a rich Tory and found that he liked it (but no whips, he has personal experience on the wrong side of those). They have sex and discuss books and current affairs, but neither knows the other's name, so things take a turn when they each realize that Frey works for the home office and Mason is running an illegal, radical print shop in his book store.
I loved this book. I love me some 18th/19th century radical politics, and K.J. Charles may do the combination of sex and politics better than anybody else. Mason and Frey are both deeply principled men but capable of friendly disagreement, which might be as beautiful an example of wish fulfillment fantasy as anything else that's ever been seen on the pages of a romance novel, and tightropes they walk so as to maintain their relationship while remaining true to their beliefs will keep you enthralled until the last page.
Overall: A