Jon Sinclair and his grandmother have been flung back in time from 2010 to 1692, where Jon has been shanghaied for work as a cabin boy on a pirate ship under the command of BlackHeart, and his grandmother has disguised herself as a man to work as a cook on a rival pirate ship. Since the respective ships are captained by rivals, Jon and his grandmother may end up having to battle each other. Meanwhile, back in Missouri, Jon's grandfather tries desperately to reach and retrieve his wife and grandson.