Mystery: Sherlock Holmes.

Musing on the mysteries of the case, Watson dismisses the supernatural explanation but admits that his common sense offers no obvious solution. Where might a living and breathing hound hide by day, and who is the mysterious shadow out on the moor? Watson determines to find out what this man might know and whether he is the same person who provided the warning back in London.
Meanwhile, Sir Henry argues with Barrymore over the chase of his brother-in-law, Selden. Watson and Henry worry that the man is a public danger. Nonetheless, Barrymore assures them that Selden is just biding his time u…