Tom Clancy's Rainbow Six: Lockdown is the fourth game in the Rainbow Six series. The player controls the main character, Rainbow leader Ding Chavez, and leads a single squad in real-time through each level. The player can issue orders to team members, such as to break down a door or toss a grenade into a room.
Lockdown takes place in 2009 and revolves around an elite counter-terrorist unit called Rainbow. In Lockdown, Rainbow is pitted against a worldwide terrorist organization known as the Global Liberation Front, composed of various leftist, anarchist, and third-world organizations opposed to the West. The Global Liberation Front has stolen a man-made nanotech virus named "Legion". "Legion" is a nanite aerosol that causes massive hemorrhaging in its victim and has a mortality rate of 100%. Rainbow must find and stop the GLF from using the virus. To accomplish this, Rainbow goes from country to country, tracking down each country's GLF cell, and finally capturing or killing that cell's leader, ultimately leading to a showdown with the GLF's supreme leader, Bastian Vanderwaal. A major plot twist occurs when team sniper, Dieter Weber, is captured by the terrorists, prompting an unauthorized rescue effort by the team. The game includes 16 single-player missions in all (14 on the Xbox).
Source: Wikipedia, "Rainbow Six Lockdown", available under the CC-BY-SA License.