Work is underway on the destruction of deadly substances in a sealed-off factory under the highest security precautions. Then the lead chemist Dr. Diestel kidnapped. A cartridge of sarin gas is stolen with him. A poison that kills silently, invisibly and odorless within a few minutes. Enough for an attack, enough for an act of terrorism. As quietly and unnoticed as the theft took place, the hunt for the perpetrator must also be secret. Do not stir up panic and no invitation to free riders, so prosecutor Anton Mehringer. He entrusts Sarah Kohr with the investigation - without a stir, but with full authority. She finds out that there is no terror cell behind the theft, but that the perpetrator was guided by a very personal motive for revenge. When Sarah Kohr can secure the warfare agent, the nightmare is far from over, but escalates into an immense threat.