Detectives Klaus Weber and Anna Müller sat in their office at the Eimsbüttel Police Station, enveloped by the murmurs of conversations and the occasional jingle of ringing telephones. The day had unfolded unremarkably thus far, but an imminent shift in events was about to transpire. Suddenly, the voice of their superior crackled through the intercom, shattering the monotony.

"Klaus, Anna," the voice called out, "I need you to head to the Stadtplanungsbüro on Graumannsweg 69 and obtain the blueprints of the sewer system in Graumannsweg. I need you to find out where the manholes outside the Indian consulate are connected to."

Their gazes met, momentarily exchanging curiosity before transforming into resolve. Gathering their belongings, they stepped out into the inner courtyard, settling into their compact BMW 3 Series police car, and made off to the planning office, some five kilometers away, on the opposite side of the Außenalster Lake.

The planning office bustled with activity as architects and engineers scurried about, engrossed in their projects. Klaus and Anna approached the reception desk, where a friendly receptionist greeted them.

"We're from the Hamburg police," Klaus explained, "and we require access to the blueprints of the sewer system in Graumansweg."

The receptionist nodded in understanding, guiding them towards a small room housing the blueprints. Stepping inside, they were greeted by meticulously organized filing cabinets, neatly aligning row after row. With purposeful strides, the receptionist located the section devoted to Graumansweg, promptly extracting the relevant drawer.

Their eyes scanned the blueprint, tracing the path of the sewer lines that crisscrossed Graumansweg. It didn't take long before they spotted the familiar markings that indicated the location of the manholes. Each manhole was connected to only a small number of houses along the street. "We just need copies of this one and this one, I believe, the Indian consulate is here." Klaus pointed on the map. Anna nodded.

The cool air of a crisp Hamburg noon mixed with the bright sunshine and bathed the city streets in freshness, awakening anyone who took a step outside in the sleepy March neighborhood. The tranquility was briefly interrupted as the detectives cordoned off the manhole using bright yellow caution tape. Two or three onlookers briefly stopped out of curiosity.

Klaus Weber, a junior detective with a keen eye for detail, examined the lid covering the manhole, then grasped a crowbar and lifted it away, disclosing the opening straight down.