Rose - Its shades of grey

Is it just a coincidence that the murder weapon in a mysterious murder case is identical to the name of the main suspect's lover?
Karl Dreher has been on the run in his motorhome for days, fleeing from Dortmund to the south, across France and the Pyrenees. His goal: Madrid, where his mistress Rosa is waiting for him, the woman who changed his life from the ground up.
But what about her enigmatic messages? And what is behind the blackmail attempt of an anonymous perpetrator who demands payment in Bitcoin?
A dark as well as exciting thriller in the area of tension between love, revenge, justice and cryptocurrencies.