The Anniversary Party by Melissa F. Miller

It’s going to be a killer party, and you’re invited!

Sasha and Leo can’t wait to celebrate their tenth anniversary with their closest friends at a remote countryside estate. But their plans go awry when a massive winter storm moves in, cutting off the power, phones, and any chance of leaving.
Trapped in the sprawling manor with their quirky group of pals, including a true crime podcaster, an expert tracker, and a forensic pathologist, they try to make the best of the situation. Also stuck is one other set of guests—a college reunion gathering that isn’t as festive as it seems.
The situation goes from snowy to chilling when one of the reunion guests turns up dead. With no way to contact the authorities, it’s up to quick-witted lawyer Sasha and her clever federal agent husband Leo to piece together the clues and unmask the killer in their midst.

The Anniversary Party is a sharp, suspenseful, and twisty mystery in which every move counts and every offhand remark might be a clue. It’ll keep you guessing until the very end.