Lost Hours by Susan Sleeman

Protecting his friends has always come first…
When Nolan Orr, founding member of Lost Lake Locators, and his teammates receive a mysterious invitation to a secluded mansion on Lost Island for what seems to be an innocent game night with his closest college friends, he eagerly agrees to attend. Not only to enjoy the event with friends who were more like family to him than his actual family, but to figure out which friend set up the fun but unusual night.
Until he has to consider one of them a suspect for murder.
However, as the evening progresses, he soon realizes that they are pawns in a deadly game orchestrated by a twisted mastermind. Where betrayal and survival go hand in hand, ultimately leading to a missing friend, to murder and a murder investigation that Sheriff Mina Park arrives to take charge of. Problem is, Nolan and Mina had a brief summer fling one year on his visit to the island, and it ended badly. Will she let him into the investigation and work with him, or avoid him as she’s been doing for years?