The setting is around the early 60's on the British countryside. Some escapees from a prison in "Dartmoor" where killed mysterious in the near swamp territory. A P.I. gets challenged to solve the case.
So, a storyline we've seen nearly a thousand times, which isn't really convincing in this case.
The acting is temporarily pretty poor, some shots are just cheesy, and, what annoys me the most, the actors and the scenery are German, yes, even the plate of the prison, is written in German, although it takes place in Britain. The transitions of both, the German and the British aspects and props, are mixed and blurred in some ridiculous forms. The names and attitudes of the characters are so much stereotyped, it seems, the production team didn't took much work on that.
But the soundtrack is very nice, good matching parts for some different shots and scenes.
All in all i was only able watching it, by not taking it serious and seeing it as a parody or comedy. But hey, give it a chance, there are a lot of movies out there, which are way worse than this.