Arjun had read the first edition of Forensic Medicine and Toxicology by Ignatius P. X. as a first-year student, the pages already dog-eared and coffee-stained. He’d memorized the chapters on asphyxiants, poisons, and post-mortem lividity. But no textbook could prepare him for the smell of a life interrupted.

But there was no source of carbon monoxide.

Arjun’s scalp prickled. He drew blood from the femoral vein and watched it drip into a vial—it was unnaturally bright red, almost festive. A spectrophotometer confirmed it: 68% carboxyhemoglobin.

Carbon monoxide , whispered the voice of the textbook in his head. Forms carboxyhemoglobin. Gives blood and tissues a characteristic cherry-red hue.

Then he saw it.

The case was closed. Not murder. Not suicide. An industrial accident written in the color of her blood.