The monsoon rains battered the tin roof of our modest flat in Harrison Road, Calcutta. I, Ajit Banerjee, sat by the window, scribbling notes for my next story, while Byomkesh Bakshi lounged on the divan, puffing his pipe. The air was thick with the scent of tobacco and damp earth. It was a quiet afternoon—too quiet, perhaps, for a man like Byomkesh, who thrived on puzzles.

The knock came at precisely 4:17 p.m. A soaked figure stood at our door, water dripping from his umbrella onto the mat. He was a wiry man in his fifties, with a pinched face and nervous eyes. “Are you Byomkesh Bakshi, the satyanweshi?” he asked, his voice trembling.

“I am,” Byomkesh replied, setting his pipe aside. “And you are?”

“Pranab Chatterjee. I need your help. Something terrible has happened.”

We ushered him in, and after a cup of tea steadied his nerves, Pranab began his tale. He was a clerk at a jute mill, living with his wife, daughter, and elderly mother in a small house in Shyambazar. Three days ago, his mother’s gold locket—a family heirloom—had vanished from her locked almirah. The locket wasn’t just valuable; it held a miniature portrait of his late father, making it irreplaceable. The police had dismissed it as a petty theft, but Pranab suspected something darker.

“There’s more,” he said, lowering his voice. “Yesterday, I found a note slipped under my door. It said, ‘The locket is only the beginning. Pay or lose more.’ I think someone’s watching us.”

Byomkesh leaned forward, his eyes gleaming. “Who has access to your home?”

“My family, of course. And… well, there’s Binod, our servant. He’s been with us for years, but lately, he’s been acting strange—furtive, you know?”

“Interesting,” Byomkesh murmured. “Ajit, pack your notebook. We’re going to Shyambazar.”

The Chatterjee household was a cramped, two-story affair, its walls stained with mildew. Pranab’s wife, Lila, greeted us with a forced smile, while their teenage daughter, Rina, hovered in the background, her eyes red from crying. The grandmother, a stern woman wrapped in a white sari, sat in a rocking chair, clutching a walking stick. Binod, the servant, was nowhere to be seen.

Byomkesh examined the almirah in the grandmother’s room. The lock was intact, with no signs of tampering. “Curious,” he said, tapping the wood. “A key must have been used. Who keeps the keys?”

“I do,” the old woman snapped. “And I never let them out of my sight.”

“Never?” Byomkesh pressed.

She hesitated. “Well… I might’ve left them on the table once, when I went to bathe.”

Byomkesh nodded, then asked to see the threatening note. Pranab handed him a crumpled scrap of paper. The handwriting was jagged, as if written in haste. “Hmm,” Byomkesh said, folding it into his pocket. “Ajit, let’s take a walk.”

Outside, the rain had softened to a drizzle. Byomkesh led me down a narrow alley behind the house, his keen eyes scanning the mud. He stopped abruptly, pointing to a set of fresh footprints leading to a shed. Inside, we found Binod, hunched over a wooden crate, counting a stack of rupees. A glint of gold caught my eye—the missing locket.

“Binod!” I exclaimed.

He froze, then bolted for the door, but Byomkesh tripped him with a deft flick of his foot. “Sit,” he commanded. Binod obeyed, trembling.

“Explain yourself,” Byomkesh said.

Binod’s story tumbled out in a rush. He’d stolen the locket, intending to sell it to pay off gambling debts. But he swore he hadn’t written the note. “I’m no blackmailer, sahib! I just needed the money!”

Byomkesh studied him, then turned to me. “Ajit, do you notice anything odd about this?”

I frowned. “The note said ‘pay or lose more.’ If Binod already had the locket, why demand payment?”

“Exactly,” Byomkesh said, a faint smile tugging at his lips. “Someone else wrote it. Someone who knew the locket was gone and saw an opportunity.”

Back at the house, Byomkesh gathered the family. He held up the locket, watching their reactions. Lila gasped, Rina paled, and the grandmother’s eyes narrowed. Then he produced the note. “This was written by someone inside this house,” he declared. “The ink matches the pen on Rina’s desk.”

Rina burst into tears. “I didn’t mean any harm! I saw Binod take it and thought… if I scared Baba into paying, I could use the money to run away with my boyfriend. I hate this house!”

Pranab stared at his daughter, stunned. Lila began to sob. The grandmother muttered something about disgrace.

Byomkesh handed the locket to Pranab. “The case is solved. Binod stole it, Rina exploited it. I suggest you deal with this as a family.”

As we left, the rain had stopped, and the air felt lighter. “Another triumph, eh, Byomkesh?” I said.

He chuckled. “Triumph? No, Ajit. Just truth. That’s all I seek.”

And with that, we walked back into the bustling heart of Calcutta, the city that never ceased to surprise us.