A kidnapped musician and his missing violin are the prelude to a series of murders whose victims were deeply involved in business connections between the GDR and Austria. The investigators of “SOKO Donau/Wien” and “SOKO Leipzig” work together to solve a cross-border case.

Leipzig Gewandhaus. Philipp (Dominik Maringer), a virtuoso violinist from Vienna, is celebrating with fan Luna after the concert. While she is in the bathroom, there is a knock at the door. But it’s not room service, it’s a stranger with a stun gun. And then Philipp disappears. The trail leads to Vienna. The “Soko Donau” has to work closely with their colleagues in Leipzig. What does all this have to do with Philipp’s violin, which he received from his old Viennese violin teacher?