In amongst the cluttered sprawl of artifacts in 221B Baker Street lies a quiet treasure. A coin, given in gratitude to Sherlock Holmes by the British Treasury. He must keep it safe from the criminal underworld where it could bankroll any number of nefarious schemes. Mulling over a cold case he senses inspiration. Taking an old safe, he modifies it with a series of panels, notches, and tiles that, only when manipulated in a specific order, will allow the safe to open.