The Coroner and the Seventh Door

Qin Feng is the youngest forensic examiner in the city bureau, and the only person ever to see the "Seventh Door."

Three years ago, he found a bronze key engraved with a six-pointed star inside the lungs of a drowned woman. That night, footage from the autopsy room showed Qin Feng offering his scalpel to empty air at 3:07 a.m., before bloody handprints suddenly covered the camera lens.

Now, the sixth "ritual murder" has taken place. The victim's frontal bone was drilled with a keyhole-shaped wound, and their stomach was stuffed with swollen, waterlogged fragments of the Extensive Records of the Taiping Era. As Qin Feng scanned the body with a laser, black water suddenly seeped from the autopsy table, revealing the reflection of the key from three years ago.

Criminal psychologist Su Yuqing wrote a chilling discovery on the case board:

"Connected together, the six crime scenes form a map of the body's seven apertures."

"And the seventh coordinate..." Her pen trembled. "It's in Qin Feng's autopsy room."

The latest entry in the midnight duty log:

"2023.12.24. Forensic examiner Qin performs an autopsy alone. At 2:15 a.m., he speaks to the empty morgue and says

'Give me back the key.'"