Mystery Title: The Case of the Missing Heirloom

Characters:

• Arthur Blackwood (Victim): A wealthy, elderly gentleman with a neatly trimmed white beard, thinning grey hair, and a penchant for tweed jackets. He is known for his eccentric collection of antique clocks.
• Eleanor Blackwood (Arthur's Wife): A sharp-tongued woman in her late 60s with dyed blonde hair and a perpetually disapproving expression. She wears expensive, but slightly outdated, clothing. She is known to be fiercely protective of her husband's possessions.
• Charles Blackwood (Arthur's Nephew): A charming but impecunious man in his early 30s with dark, wavy hair and a perpetually nervous demeanor. He is always impeccably dressed, despite his financial struggles.
• Ms. Agatha Plum (Housekeeper): A middle-aged woman with kind eyes and a practical demeanor. She wears simple, functional clothing and always keeps her hair neatly tied back. She has worked for the Blackwoods for over 15 years.
• Detective Inspector Davies: A seasoned detective with a keen eye for detail and a no-nonsense attitude. He is middle-aged, with short, greying hair and a perpetually serious expression.

Setting: The Blackwood Manor, a large, Victorian-era house filled with antique furniture and numerous clocks. The robbery took place in Arthur Blackwood's study.

The Robbery: A valuable antique clock, the "Blackwood Chronometer," has been stolen from Arthur Blackwood's study.

Clues:

1. Broken Window: A small window in the study is broken, suggesting forced entry. However, the window is unusually high, making it difficult to reach from the outside.
2. Displaced Books: Books on a shelf near the window are knocked over, but in a strangely organized manner, not the chaotic scattering one would expect from a forced entry.
3. Footprints: Small, muddy footprints are found leading from the broken window to the study's fireplace. They are too small to belong to Arthur, Charles, or the Detective.
4. A Torn Glove: A piece of a leather glove is found near the fireplace, matching the style of gloves worn by Charles Blackwood.
5. A Missing Clock Key: The key to the Blackwood Chronometer is missing from its usual place on Arthur's desk.
6. A Smudged Fingerprint: A smudged fingerprint is found on the inside of the broken windowpane. Analysis reveals it belongs to Ms. Plum.
7. Eleanor's Testimony: Eleanor claims she was asleep during the robbery and heard nothing. However, she is found wearing a pair of expensive, new earrings that were not seen on her before.
8. Charles's Alibi: Charles claims he was at a friend's house all night, but his friend's testimony is vague and unconvincing.
9. Ms. Plum's Statement: Ms. Plum admits to touching the window while cleaning, explaining the fingerprint. She claims she didn't notice the broken window until the morning.
10. Hidden Compartment: A hidden compartment is discovered behind the bookshelf, containing a duplicate key to the Blackwood Chronometer and a note signed by Eleanor, revealing her plan to sell the clock to pay off a large gambling debt.

Solution:

Motive: Eleanor Blackwood, burdened by gambling debts, orchestrated the robbery to sell the valuable Blackwood Chronometer.

Method: Eleanor, with the help of her nephew, Charles, planned the robbery. Charles, being small and agile, entered through the high window. He then used the duplicate key to steal the clock. The organized displacement of books was a deliberate act to mislead investigators. The muddy footprints were planted to further confuse the investigation. Eleanor's new earrings were purchased with the money from the sale of the clock. Ms. Plum was unaware of the plot, her fingerprint being a result of her cleaning duties.