Sherlock Holmes in The Adventure of the Graphite Cipher

When a Patent Office clerk brings Sherlock Holmes a fragment of paper covered in mysterious graphite smudges, Holmes dismisses the case as trivial—but the death of a brilliant chemist and a violent assault soon follow. What begins as apparent foreign espionage reveals itself to be something far more complex and dangerous.

As Holmes pursues the truth through graphite mines, chemical laboratories, and the shadowy world of industrial patents, he discovers that his initial solution was merely the surface of a conspiracy that reaches across Europe—and that his greatest mistake may have allowed a killer to continue his deadly work.