Series numeration from goodreads.com.

"Originally published by Bookouture in 2020. An imprint of Storyfire Ltd. ... London"--Copyright page.

"The first time Jemma and Matt were invited to Polskirrin -- the palatial ocean-view home belonging to Matt's old friend Lucas Jarrett -- it was for an intimate wedding that ended in tragedy. Jemma will never forget the sight of the girl's pale, doll-like body bobbing listlessly toward the rocky shore. Now, exactly one year later, Jemma and her husband have reluctantly returned at Lucas's request to honor an anniversary they would do anything to forget. But what Lucas has in store for his guests is nothing like a candlelight vigil. Someone close remembers more from that night than they'll admit to, and Lucas has devised a little game for them all to make them tell the truth. At least Jemma knows that she and Matt weren't involved in what happened to that young woman ... or were they? Before you play a game with death, make sure you can pay the price"-- Provided by publisher.