Winnie Rose is a part-time ballerina, part-time student, and part-time cabbie. She's an American in London, daughter of U.S Marine Corps Scout Sniper turned NCIS special agent, and she unknowingly has a target on her head. In balancing the many aspects of her life, she comes into contact with Sherlock Holmes and John Watson, and finds herself at the centre of a case that has been ongoing for her whole life.