Detective Sherlock Holmes finds himself in unfamiliar territory, unable to delve into a dark case without endangering his dearest companions. During this challenging time, he encounters Amelia, an American woman who, following her mother’s enigmatic death, discovers that Sherlock might be her long-lost father. Despite their vastly different upbringings and perspectives, they must join forces to unravel a worldwide conspiracy, solve her mother’s murder, and determine if Amelia truly is Sherlock’s daughter.