Exclusive to Audible. J. S. Law reveals how his time in the Royal Navy influenced his book, Tenacity, and how the lack of a true female heroine spurred him to create the central character, Danielle. About Tenacity: Suicide must be investigated. Especially when a Royal Navy sailor kills himself on a nuclear submarine only days after his wife's brutal murder. Now Lieutenant Danielle Lewis, the navy's finest special branch investigator, must interrogate the tight-knit male crew of HMS Tenacity to determine if there's a link.