Holmes and Watson try to work a stateside investigation from London when someone close to them is gravely wounded by an unknown perpetrator in the United States. However, Holmes’ stateside legal trouble – the result of a confession to a murder he didn’t commit – threatens to derail their efforts.

After an explosion at a traffic stop, Holmes and Watson must determine whether the attack was a terrorist attack; Holmes and Watson suspect there is more for them to discover regarding the recent attack on someone within their inner circle.