Tove and the Island with No Address

"Tove and her family go to the island with no address every summer. After checking to make sure that everything in the cabin is exactly as it should be, young Tove sets off on an adventure. She finds some interesting salvage on the beach, she visits the grotto, and she offers to babysit her strange little friend's five wild daughters. But when the weather takes a turn, Tove finds this task is more than she bargained for"--