"A ride aboard a luxury submarine leads to oceans of trouble for Ireland's Crown Princess..." From an Ireland that might have been to the perils of parallel worlds, warrior princess Talty Boru has outwitted all sorts of scoundrels. A wife and mother at last, the dynamic heir to the Irish throne believes her days of exotic adventure are done and dusted. Yet her royal duties seem endless, and a day off with handsome husband Neil is looking good. Former naval officer Talty eagerly accepts an eccentric billionaire's invitation for a jaunt aboard his luxury submarine, but as she and Neil dive beneath the waves to view an eerie shipwreck, a sinister plot unfolds. An unknown enemy lures them to an ancient tomb and sends them to a world infested with treacherous pirates. Talty takes charge of a pirate ship and its mangy crew, while Neil matches wits with a steamy temptress who jeopardizes his wedding vows. As he and Talty battle to save their marriage, they learn that the door to parallel worlds swings both ways...