Last we seen of John and Mary Watson, Mary was very pregnant with a baby girl. And now, it's time for Cassandra Watson to be born. As she grows up, Cassandra forms a close bond with her father's best friend and her godfather, Sherlock Holmes. But, back when Cassandra was just a fetus in her mom's stomach, Sherlock's biggest enemy and threat, James Moriarty, returned. Sherlock and John have been waiting many years for him to finally strike, and now he has. And his big plan includes a little Watson.
