"Harbour" by John Ajvide Lindqvist

Lindqvist's 2008 novel is part nautical ghost story, part little-girl-lost, part love story, part wtf!
Water, water everywhere. Don't mess with the sea. Like is far from idyllic on the fictional island of Domaro.
It's nutty but a great read nonetheless.  Like Stephen King (who Lindqvist has been compared to), he writes perceptively about young teens (his debut novel was "Let the Right One In"). The author is at his best when he writes about teenagers and this time there are several key back stories involving kids. I prefer his biting "Little Star" to "Harbour".
It's a bit of a mishmash. You have elements of "The Birds", "The Wicker Man", some cursed village from a 60's Hammer movie, a Swedish Houdini and sci-fi (e.g. Spiritus, the water-controlling larva who lives in a matchbox and requires a daily gob of saliva from its owner).
The three main characters (the octogenarian lovebirds, Simon and Anna-Greta and their tortured grandson, Anders) are beautifully drawn. Best bits are the stories from the island's murky past, a ripping yarn about Simon the escapologist and flashbacks to Anders' 1980's teenage years with lots of musical references (from The Smiths to Frankie goes to Hollywood).