The wealthy and passionate collector of antiquarian books Maximiliane Schlösser is found dead in her villa. She appears to have bled to death from being stabbed with a dagger. For the chief inspectors Ehrlicher and Kain, everything points to a robbery and murder. But Mrs Schlosser's cousin and assistant Dr. Ursula Hertel state that nothing was stolen from the villa. But the inspectors find a color copy of the lost "blood writing" under the dead body. This, the inspectors learn from Professor Berg, the chief librarian of the German library, is a thousand-year-old manuscript that a Benedictine monk is said to have written with his own blood. The old and extremely valuable book is said to have always brought death and ruin to its owner.
The autopsy shows that Ms. Schlösser only injured herself with the dagger and was killed by a blow to the head. The commissioners assume that the solution to the case is related to the coveted "blood writing". Forensic technician Walter puts the inspectors on the trail of Jens Tegner, a book restorer with whom the collector spoke on the phone shortly before her death. However, Ehrlicher only finds his ex-girlfriend Silke Weinrich and a packed travel bag in his apartment. Silke suspects that her ex-husband wants to travel with his new love Martina Matussek - Prof. Berg's new assistant. When the fluff that Ehrlicher took from a Tegner pullover turned out to be identical to those found at the scene of the crime, the inspectors launched a search for the suspect Tegner.
Valuable books are also stolen from the villa of the murdered and a mummified corpse turns up. The inspectors find out that Silkes Weinrich's father, who runs a small antiquarian bookshop, used to work in East Germany with the help of his assistant at the time, Dr. Hertel sold books to the West - his business partner at the time was Maximiliane Schlösser...