The Frye twins are approached by Henry Raymond, a penny dreadful writer, as well as his follower, a young Arthur Conan Doyle. They team up to investigate a series of murders across London, visiting crime scenes, gathering evidence, interviewing witnesses and suspects, and ultimately solving the crimes by accusing the true perpetrators.

The twins are eventually summoned to Buckingham Palace by Queen Victoria, in order to solve the murder of one of her guards. It turns out that it is in fact Raymond who has posed as a guard and faked his own death, so he may steal the Queen's Sceptre of the Dove by observing up close the combination to the safe that holds it. He has also left a series of false clues suggesting a bomb threat in the palace in order to cover his escape. However Doyle has already uncovered his plan and set out to stop him, but is held hostage on the palace roof in the process. One of the Fryes manages to distract Raymond while the other sneaks up and kills him, saving Doyle and recovering the Sceptre. In the aftermath, the Fryes encourage Doyle to try his own hand at writing detective fiction.