Race to the bottom of the sea

When her parents, the great marine scientists Dr. and Dr. Quail, are killed in a tragic accident, eleven-year-old Fidelia Quail is racked by grief--and guilt. It was a submarine of Fidelia's invention that her parents were in when they died, and it was she who pressed them to stay out longer when the raging Undertow was looming. But Fidelia is forced out of her mourning when she's kidnapped by Merrick the Monstrous, a pirate whose list of treason...