A neurosurgeon hits a child one night and, in a panic, commits a hit-and-run. The next day, she finds the boy on her ward of all places, a Romanian street kid who is being forced to pick pockets by a gang. The boy, who recognizes the driver from the accident, blackmails the doctor out of fear of the police and his gang. She is forced to give him shelter, but the two soon become friends and form a tight-knit community.

Reluctantly, Rüdiger and Marlene agree to a blind date and, to their surprise, they hit it off straight away. The happiness of the newly in love couple has just one flaw: in order not to scare their partner away, they conceal the fact that they have children. A crazy game of hide-and-seek begins, which really gets on the nerves of their two children, Stella and Max. Stella and Max meet by chance and decide to end their parents' chaotic relationship with an intrigue. But when it turns out that Marlene is pregnant, the kids have to take their parents' fate into their own hands again.

The body of a homeless man is found in Cologne not in the Dark Ages, but in the year 2000, where an autopsy reveals that he died of the plague. Doctor Martin Brügger sets out to find the cause and discovers masses of dead rats in the sewers. The population of the Rhine metropolis is in danger - but the authorities do not want to cause panic and keep the case a secret.