After Tom's latest adventure on and inside the Moon, he decides to take on a new project, one for a paying customer of Swift Enterprises. unlike many of his adventures having to do with one ocean or another, this time he will be entirely on the top of it. Or, more correctly, above it.Although not one of its primary markets, the Swifts have built at least one super yacht, so when a very rich man living in Ireland contacts Tom with a request for a very unique new sort of yacht, the inventor considers passing, but comes to the decision that his family needs him to remain grounded for awhile. So, with a budget that is, to his thinking, almost obscenely inflated, and a request that the yacht be so individualized it might never be repeated in the form designed by the inventor, he sets forth to build the nearly impossible.Tom Swift likes building the nearly impossible.The "fly" int he ointment comes in the form of a group who are out to pirate anything on the high seas they see as advantageous to their continued operations, and they have one heck of a way to get around that the inventor must either avoid or find a way to defeat.