A mysterious murder occurs on board the Elbe, a ship sailing from Europe to America. And where there is a murder, and especially a mysterious murder, there is always something to puzzle Arthur Conan Doyle, a great lover of such mysteries, over. He soon finds out that the cause of the crime was a book about the principles of Kabbalistic teachings, which was stolen from the unfortunate victim. In addition, similar disappearances of sacred books have already occurred in different parts of the planet. And in all cases, the traces of the kidnappers lead to a mysterious black tower, which persistently appears in a dream to the chosen ones, the number of which is six.