West of Wisdom

Many years ago Blake Bernard married Ethyl, the daughter of a missionary couple, on a South Pacific island. On their honeymoon cruise they were captured by pirates and the pirate captain attempted to ravish the bride. In the fight, Blake was shot and the pirate's boat caught fire and sank. Ethyl and the pirate escaped, but his treasure chest was lost. Ethyl was a grandmother when she received a mysterious riddle, West of Wisdom, found in a floating bottle.
Astarte, her granddaughter, takes an inter-island freighter to find the island where her grandmother was married. When she recites the riddle to the ship's captain, who happens to be the same now much older pirate, he decides she knows the whereabouts of his long lost treasure. She is kidnaped bound and gagged and stuffed in a sail bag.
The story starts when a man with a glass eye puts the sack on the deck of Timothy Tyler's sailboat and threatens to take over. Tim refuses to let the man come aboard and sails out into the boundless South Pacific Ocean. When the bag falls into the sea, he looks back and sees a small white hand reaching from the sinking sack.
And then...