Last year’s Pretenders’ Ball had ended in the tragic assassination of the Grand Duke. Despite that disaster, the prime minister insisted on going ahead with this year’s festivities. One new concession was made to security. The Ball would be held during the day, giving the secret police a clearer view of the proceedings.
A bright, sunny sky greeted the costumed revelers. As usual, they were searched. The rubber daggers piercing Julius Caesar’s toga were allowed in, but only after a long argument. The cowboy handed over his plastic six-shooter but got to keep his rope. And Joan of Arc was permitted to keep her stake, as long as she remained firmly tied to it.
Security agents surrounded the new Grand Duke as he mingled with his guests in the festively decorated gardens. The orchestra was in top form and the ball proceeded without a hitch—until fire broke out in the royal archives.
The archives, a small stone building in a secluded corner of the palace grounds, held the tiny nation’s most revered, and highly flammable, documents. The fire was soon put out, but the documents had all been irretrievably ruined—a strong psychological victory for the rebels.
Hercules (chief of the secret police) borrowed a magnifying glass from Sherlock Holmes (royal stable master) and examined the damaged archive building. A stream of sunlight poured through the archive’s only window, still intact and locked from the inside. And the only key to the only door was safe in the Duke’s jacket pocket. “The fire started from inside,” Hercules moaned. “That much is clear. And yet no one could have gotten inside.”
Napoleon (the prime minister) gazed about at the assembled guests. “I can guess how it was done,” announced the clever politician. “And only one person could have done it.”
WHODUNIT? AND HOW?
The prime minister knew there was one sure way to start a fire inside a locked building, as long as the building had a window receiving direct sunlight. A lens could be used to focus light on any highly flammable object, such as an old document. And it works through window glass. The only costumed guest who had come prepared with just such a lens was the royal stable master, Sherlock Holmes.