In the summer of 2011, when a plague caused by the unknown pathogen EHEC-O104 suddenly breaks out in northern Germany, experts are at a loss. Marie, the girlfriend of Kiel microbiology student Harald Pütz, becomes the first victim of the outbreak. The hunt for EHEC-O104 begins, but the rapid spread of the bacteria leaves researchers no breathing room. Within a few weeks, over 4,000 people fall ill, and notably, young women are dying from the outbreak at an alarming rate. Microbiologist Leo Schneider at the Berlin Institute for Food Control and Hygiene is tasked with finding the source of the pathogen. Schneider engages in what seems like a hopeless battle against a cartel of ignorant bureaucrats, power-hungry politicians, and unscrupulous colleagues who are intent on keeping the true background of the outbreak in the dark. Schneider's opponents will stop at nothing to protect their interests.