A consulting detective, Sherlock Holmes, is called in to solve cases that prove intractable to typical state detectives, by using means of logical analysis.
In Season 3, John and Lestrade try to move on with their lives after Sherlock's apparent death. However, Anderson believes he is still alive, and Mycroft invites Sherlock back to London to investigate a secret terrorist organization.
In season 4, Sherlock Holmes and Dr. John Watson face an onslaught of disasters, as they continue to solve various crimes and find the perpetrators.