The seaport of Ys was destroyed by flood so the survivors built a village of wood. The village was destroyed by fire so the survivors rebuilt it in stone and it became the modern city of Quimper. The former King of Ys devises an ingenious plan to fund the speedy rebuilding of his colony: raid the island lairs of pirates and appropriate their loot - thus, simultaneously fund the rebuilding of civilization and root out piracy.
This must be the most ingenious and inspiring struggle for survival and prosperity in any of Poul Anderson's works. This one, The King Of Ys, is co-written by Karen Anderson.