The Chessmen, by Peter May

I really enjoyed this third entry in a trilogy following The Blackhouse and The Lewis Man. Fin Macleod has taken a job providing security on an estate further south on the Isle of Lewis, and he's tasked with stopping his old friend Whistler from poaching. When Fin follows Whistler into the mountains, a storm approaches quickly and they have to take shelter overnight. When they emerge the next morning, they find that a lake has drained from the effects of a bog burst revealing the wreckage of a small plane long thought lost at sea and which contains the body of one of their oldest friends, and it appears that he was murdered. Fin is determined to find out what happened so many years ago and why Whistler appears to be hiding something. Once again, long lost history catches up with Fin and others and the plot goes back and forth between events of 17 years ago and the present day. Peter May continues to write compelling prose with this last book in the trilogy. Published in 2012, it was followed up in 2024 with a continuation of Fin's story. Can't wait to read that one!