In the Grand Duchy of Luxembourg the days elapse peacefully and life resembles a long quiet river. It is therefore not surprising that the announcement of the murder of several young students has the effect of a huge paving stone thrown into a pond that nothing seemed to disturb. For the inhabitants of the country, not used to experiencing this kind of tragedy outside the safe confines of their TV station, this shocking crime defies understanding. To Commissioner Meyer and Inspector Thill, leading the investigation, it is the beginning of a particularly tough puzzle, since their investigative efforts do not provide the slightest element of response on the identity of the murderer. And for a good reason : the killer has left no trace and seems to have acted without apparent motive. When another victim is found dead, the fear of the Commissioner seems to be confirmed: a serial killer spreads fear and panic in the Grand Duchy. While the Commissioner tries to pre-empt the murderer before there will be more victims, which would certainly plunge the whole country into total paranoia, a few students are committed to not wait idly that the enigmatic killer strikes again. However, neither the police, nor the students are ready to face the terrible truth…