At the end of The Pirate Captain's Daughter, Catherine and cabin boy William are marooned on Pox Island by the murderous crew of the pirate ship Reprisal. The young lovers see no hope of escape.
In Voyage of the Sea Wolf, the continuing saga of Catherine's sea adventures, she and William are rescued from their island prison by the Sea Wolf, a pirate ship pursuing the Reprisal. Catherine worries that these new pirates will send her back to the island once they discover she's a girl. But then, she meets the captain of the Sea Wolf. A Woman! Surely, Catherine thinks, the bloodshed and brutality she and William experienced aboard the Reprisal can't happen again, especially under the leadership of a female captain. But just as things seem to be going their way, the captain takes a liking to William. Catherine is forbidden to see him.
If Catherine and William want to stay together, they must find a way to now escape from the Sea Wolf.