The magic envelope theft

The magic envelope theft is the most ingenious financial legerdemain in Gaston Leroux's The Phantom of the Opera, the mechanism by which the Opera Ghost, Erik, systematically extracts his monthly allowance of twenty thousand francs from the managers Firmin Richard and Armand Moncharmin while leaving them baffled and accusing each other. The scheme combines a simple substitution trick performed by the box-keeper Mme. Giry with a hidden trap-door in the managers' own office, and it succeeds twice before the managers finally understand that they have been outwitted by a master of deception who operates from within the very fabric of the Opera house.

The First Theft: The Substitution Trick

The first theft occurs when the managers, having received a note from O. G. demanding payment, place twenty genuine thousand-franc notes into an envelope, seal it with their own seal, and hand it to Mme. Giry to deliver to the ghost's box. Unknown to them, Mme. Giry is a confederate. She carries a second, identical envelope, prepared beforehand by the ghost and sealed with counterfeit seals, hidden up her sleeve. At the ghost's box, she substitutes the false envelope for the real one, then later slips the genuine envelope into the tail-pocket of Firmin Richard's dress-coat while he is bowing to the under-secretary for fine arts in the ballet foyer. The managers, having watched the envelope on the shelf of Box Five all evening, open it after the performance to find that the real notes have been replaced by twenty notes from the "Bank of St. Farce"—flash notes of no value. Moncharmin immediately suspects Richard of having taken the money himself, and a stormy quarrel ensues.

The Second Theft: The Safety-Pin and the Trap-Door

For the second payment, Richard and Moncharmin resolve to prevent any repetition. They again place twenty thousand francs in an envelope and give it to Mme. Giry, but this time they have her watched and then locked in Mercier's office immediately after she performs the substitution. Richard then walks backward through the passages to the managers' office, with Moncharmin following close behind, to ensure no one can approach him. Once locked in the office, Moncharmin pins the envelope containing the genuine notes into Richard's coat-tail pocket with a safety-pin, so that any attempt to remove it would be detected. They sit waiting until midnight, when they had left on the previous occasion. At the stroke of twelve, Moncharmin feels the pin still in place but finds the pocket empty—the notes have vanished. The pin remains, stuck in the same spot. Richard, in fury, accuses Moncharmin of having taken the money, and the two managers are on the verge of violence when the commissary of police, M. Mifroid, arrives to investigate Christine Daae's disappearance.

The Mechanism Revealed

The Persian's later investigation, confirmed by the narrator's own discovery, reveals the trick. In the floor of the managers' office, within a couple of inches from the desk-chair, there is a trap-door the width of a board and the length of a man's forearm. Through this trap-door, a hand could reach up and dexterously fumble at the pocket of a swallow-tail coat. Erik, who had been nicknamed "the trap-door lover" for his skill with such devices, had simply reached up through the floor, removed the notes from Richard's pocket, and left the safety-pin undisturbed. The trap-door was so well concealed that the managers never suspected its existence.

The Return of the Money

A few days after Christine Daae's disappearance, when the managers had made an appointment with the commissary to tell him the whole story, they found on Richard's table a large envelope inscribed in red ink "WITH O. G.'S COMPLIMENTS." It contained the full sum of forty thousand francs—both the first and second payments—which Erik had "playfully extracted" and now returned. Moncharmin, in his Memoirs, records that Richard was at once of the opinion that they must be content with that and drop the business. The money was restored because Erik no longer needed it: he had relinquished his marriage with Christine Daae and, with it, his claim on the world above ground. The theft, therefore, was not mere greed but a demonstration of power—a game in which the ghost proved that he could take what he wanted and, when it suited him, give it back.