Sunken Kingdom
4 primary works
Book 1
After their parents, the rulers of the Star Lands, are deposed and their kingdom flooded, Asa and Rollo hide out until they come into possession of a ghost ship and magic powers, which they use to find the baby sister they thought had died with their parents.
Book 2
Book 3
When Asa and Rollo discover that Ragni, a sorcerer who has been chained to a rock by the evil Emperor Flood may know the fate of their parents, they set off in their invisible boat to find him.
Book 4
Asa and Rollo, acting on information they received from Ragni, the sorcerer, sail their invisible ship to Emperor Flood's stronghold, Castle Crag, to find out once and for all whether their parents are alive.