The Swallows are marooned with just a little sailing boat for company. Will they survive their chance to become true explorers? When the Walker family's holiday plans are ruined by Daddy having to work, the whole summer seems lost at sea. But a dull holiday for the children is too miserable to bear so their parents hatch a plan. The Swallows are to be marooned on an island with only a blank map and a little sailing dinghy. Their task? To explore and chart the area, avoid the endless mud and survive. And what do they discover? Well, they might not be as alone as they first thought.