Voyage to Magical North (The Accidental Pirates)

Twelve-year-old Brine Seaborne is a girl with a past . . . if only she could remember what it is. Found alone in a rowboat as a child, clutching a shard of the rare starshell needed for spell-casting, she's spent every day since housekeeping for an irritable magician and his obnoxious apprentice, Peter.

But everything changes when Brine and Peter accidentally break the magician's starshell and need to flee the island. Lost at sea, they blunder into the path of the legendary pirate ship the Onion. Before you can say 'pieces of eight,' they're up to their necks in the pirates' quest to find Magical North, a place so shrouded in secrets and myth that most people don't even think it exists.

If Brine is lucky, she may find out who her parents are and why they sent her out to sea. And if she's unlucky, everyone on the ship will be eaten by sea monsters.

It really could go either way.