It was just after sunrise on a misty Tuesday when Detective Marcus Leclerc and his Belgian Malinois, Bruno, received an unusual assignment. Dispatch had relayed multiple calls from neighbors about a vacant house on the outskirts of the Bavarian town of Regensburg. The property had belonged to an elderly widow, Frau Adelheid Krämer, who had passed away the previous winter. Although the place should have been empty, residents insisted they had seen flickering lights through the curtains at night, and some even swore they heard voices.

The authorities suspected the house might have been repurposed by squatters—or worse, for criminal activity. Marcus, seasoned in such investigations, wasn’t easily rattled. Still, he knew to trust his partner, Bruno, whose instincts often uncovered things human senses overlooked.

As the heavy oak door creaked open, Marcus immediately noticed something odd. For a house that had been abandoned for nearly a year, it didn’t look abandoned at all. The floors shone as if freshly polished, the air carried the sweet trace of lavender, and not a speck of dust lay on the windowsills.

“Too clean,” Marcus muttered to himself.

His partner, Officer Daniel Kowalski, headed upstairs to check the bedrooms, while Marcus and Bruno stayed on the ground floor. The dog sniffed diligently along the hallway, his nails clicking against the parquet.

Then, without warning, Bruno froze. His fur bristled, and he gave a low, guttural growl. His leash tightened as he lunged toward a large, framed painting hanging on the wall—a stern-looking family portrait of a woman and two pale children, painted in the 1920s style.

Marcus frowned. “What is it, boy? You smell something?”

Bruno barked sharply, refusing to back down, his eyes fixed on the portrait.

Marcus raised his flashlight and examined the painting closely. Nothing immediately appeared strange. The canvas was old, the frame chipped in a few places, but nothing that justified Bruno’s agitation. Yet Marcus had learned never to ignore that dog.

“All right, let’s see what you’ve found,” Marcus said, pulling on a pair of gloves. He lifted the heavy portrait carefully from its hook.

Behind it, his beam revealed a rectangular outline of metal embedded in the plaster wall. A safe—thick steel, equipped with a rotary dial from another era.

“Daniel!” Marcus called upstairs. “You need to see this.”

Footsteps thundered down the staircase. Daniel appeared, slightly out of breath. “A safe? In the wall?”