Bernd Ziegenhals is a former student who's fallen on hard times. When carrier-socialist Hohenberg, one of his former fellow students, offers him a research job (some literature work) he's by no means thrilled but takes the job as he needs the money and has nothing else to do anyway. This decision would change his life: when comparing different sources in the literature he discovers that Professor Kolczyk got his degree by cheating, by translating somebody else's work from English to German and presenting it as his own.
Starting from here the film goes through a sequence of mostly surprising twists and turns, beginning with Ziegenhals blackmailing the Professor. Kolczyk is no pushover though and knows how to fight back (the novel on which the film script is based was written by a professor of sociology under pseudonym).
The battle between the protagonists is set against their different social backgrounds: Kolczyk is all-established upper middle class, with a nice wife, a nice house and nice kids; Ziegenhals lives in a shared flat, and there's very little nice about his life - one of his friends, the prostitute Miezi gets murdered by her former pimp Proetzel when he's released from jail. What makes the film particularly interesting is that neither Kolczyk nor Ziegenhals is interested in an out-and-out confrontation since the main objective of both is to protect or escape their current life style.
This is an excellent movie: the suspense never falters and it is very difficult to predict the next moves of either Kolczyk or Ziegenhals (or the script) - also the ending comes as a real surprise. All this is helped by generally excellent performances from the cast, in particular the two leads Prochnow and Schwarzkopf; the cast is full of established German character actors who each could carry a film on their own and in such an ensemble it's a doddle for them.
