According to the industry trade papers, the London-set drama begins with a Russian girl who dies in childbirth. A nurse investigating her death soon discovers the girl was mixed up in sex trafficking and with the Russian mob.
Mortensen, last seen giving an acclaimed performance in Cronenberg's Oscar nominated "A History of Violence," will play a mysterious man who also has ties to the mob.
Steve Knight ("Dirty Pretty Things") wrote the "Eastern Promises" script, which is being produced by Paul Webster for Focus Features and BBC Films.
Since his three-part co-starring role in the "Lord of the Rings" trilogy, Mortensen has been very picking in his acting choices, limiting his exposure to "Violence," "Hidalgo" and the upcoming "Alatriste."