Black Coffee (02/08/1973)

Production : ZDF

Synopsis

The inventor Sir Claude Amery wants to give the thief of the formula for his latest invention the chance to return it in the dark without being recognized. He gathers everyone in the house in the library and has the lights switched off for a short time. When the light comes back on, Amery is dead. A case for the Belgian master detective Hercule Poirot.