Andrea Frierson

A man takes hostages, including Joan, and threatens to execute them unless Holmes finds the person responsible for the death of his son. As Sherlock investigates, the captor gives him 16 hours to find the perpetrator before the statute of limitations on the crime runs out.

The team is tasked with protecting a scientist who has developed a deadly technology that, in the wrong hands, could have devastating consequences to mankind. Meanwhile, Ryan and Shelby stumble on something personal of Alex's that signals a possible change in her personal life.