The Secret of the Dark Waterfall: A School Ship Tobermory Adventure (Book 4) by Alexander McCall Smith
Longlisted for the Highland Book Prize 2019
The School Ship Tobermory and its intrepid young crew are back in Hebridean waters. When a violent storm blows them off course to a remote island, they discover a fisherman's journal written a hundred years ago which tells of a mysterious shipwreck crammed with treasure.
But without a precise location, where do they start looking? An extraordinary chance encounter gives them a valuable clue. Before long, Ben, Fee and their friends realize they are not the only ones searching for the lost wreck and must face a ruthless and determined adversary who will stop at nothing to seize the prize.