Ubisoft sends along this in-house Rainbow Six: Lockdown Q&A, which is about the game's storyline. There are also some new screenshots here.

How did you come up with the darker storyline? Was there something from the original stories that made this transition a natural progression? We looked to the Tom Clancy novels Rainbow Six and The Bear And The Dragon for inspiration. In the books, we see a darker side to Clark and Chavez, as well as moral ambiguity and conflict between team members (such as Johnston's infamous "missed" shot at Worldpark). We really wanted to create some grey areas in the way that the team operates. In terms of earlier games, Rainbow Six 3 (PS2) featured a mission in which two members of Team Rainbow were captured by a terrorist group, and had to be rescued. However, we felt that the overall tone of Lockdown should be much more sinister than previous installments, given the subject matter.