His love of costly books supplies the motive for his annual theft.
Horace Danby likes to collect rare and expensive books, which he secretly buys through an agent.
The text explicitly links his carefully planned yearly robbery to his book purchases.
He robs one safe each year to obtain enough money to last twelve months and pay for the rare books he loves.
Her true identity is revealed after Horace is arrested and the real owner’s wife denies his story.
A young woman dressed in red is speaking to him. She pretends to be the lady of Shotover Grange, but is actually another thief.
Horace opens the safe, but the woman designs and benefits from the theft while leaving his fingerprints as evidence.
The real culprit in the jewel robbery is the clever young woman who deceives Horace into opening the safe and hands her the jewels.
The answer traces the planted clues before the explicit revelation.
A careful reader may begin to suspect her when she calmly confronts an armed possibility, handles the room as though performing ownership, and claims to have forgotten the safe combination. Her willingness to let a burglar break her husband’s safe is especially suspicious. The strongest clue comes when Horace removes his gloves to light her cigarette and then opens the safe: she is arranging for his fingerprints to identify him while leaving no trace of herself. The ending confirms that her confidence came from being a professional thief, not the owner.
Her performance combines local detail, social confidence and manipulation of Horace’s fear.
She speaks with quiet authority, calls the dog by name, straightens the fireplace ornaments and treats the house as familiar. She threatens to telephone the police, lectures Horace about protecting society and invents a plausible domestic problem: she needs jewels for a party but has forgotten the safe combination. She also says her husband is away and that she can have the safe repaired before he returns. Horace does not suspect her because these details fit his observations of the household, the dog accepts her, and his fear of prison makes him eager to believe any bargain that lets him escape.
The judgment balances his conventional life and cultivated motive against repeated theft.
Horace appears respectable because he runs a successful lock-making business, employs two helpers, lives quietly with a housekeeper and ordinarily behaves like a responsible citizen. Yet he deliberately robs a safe every year, so his respectability cannot make him honest. He differs from a stereotypical thief in being selective, patient and motivated by rare books rather than daily greed. He avoids violence and tries to steal only from wealthy households. Those features make him unusual, but they do not excuse his planned crimes; the opening description accurately captures his divided character.
The decisive errors are trusting the stranger and leaving fingerprints while acting under fear.
Horace carefully studied the house, servants, wiring, paths and safe, but he planned only for predictable physical obstacles. He failed when another person entered the situation. The woman exploited his fear of prison and his readiness to accept her as the owner. To please her, he removed his gloves, opened the safe and left fingerprints throughout the room. He also surrendered the jewels without verifying her identity. His technical planning was meticulous, but overconfidence and panic weakened his judgment; he understood locks better than people.