Abnezzar's Ghost: The Second Bean & Ab Mystery

Bean, Ab, and Spooky aren't planning to get into deep water, but when the find a mini-sub washed up on the shore, they can't resist the impulse to take it for a test dive. Bad idea. Soon the trio is way over their heads and fighting for their lives to escape a booby trap set by a pirate over two-hundred years ago. The question is, why had he set the trap?