The Murder at Mandeville Hall by Stephanie Laurens

Alaric, Lord Carradale, is finally ready to settle down. He doesn't want to spread the news because it means that he will be inundated with "help" from his three sisters. While he is a wolf of the ton, right now, no one knows the extent of his family fortune. God forbid the matchmaking mamas start to look into him if and, if he even hints that he might be looking at marriage, they will dig and they will start pushing their daughters at him.
He's at Mandeville Hall to show up at the house party his friend Percy throws every year but he's not ready to partake of the licentiousness as usual. Instead, he plans to retire to his own home at the end of every evening. But when he comes back after the first day, he discovers a body.
Miss Constance Whittaker has been sent by her grandfather to retrieve her cousin from a house party that is known to be rather... licentious. But she arrives too late; her cousin is dead. And Alaric is cradling her body. But she doesn't think that he is the one who killed her. Instead, she decides to team up with him to figure out what is going on. Unfortunately, there is another murder and Scotland Yard needs to be called in. As this is a titled group of people, of course, Inspector Stokes and Barnaby Adair are called in to help figure out what is going on.
This book mainly focuses on Constance and Alaric which is good for seeing their relationship grow but won't be good for the people used to seeing Barnaby and Penelope in the middle of the action. And the mystery wraps up early with a heavy romance on the romance for the rest of the book.

Three stars

Follows Confounding Case of the Carisbrook Emeralds

This book came out

Audiobook borrowed from Hoopla

Opinions are my own