When Mary Russell returns with her husband, the renowned Sherlock Holmes, home from abroad, her plans for peace and tranquillity are soon thwarted with the arrival of enigmatic painter Damian Adler. Adler, searching for his missing wife and child, leads them on a dangerous journey for answers. As the dynamics between right and wrong shift, Russell soon finds that the power of the sting can be more treacherous than she ever imagined.