The Dawn Brigade was a separatist movement based in Kaukistan, which became involved in a conspiracy with U.S. officials and businessmen prior to Day 5. The group was responsible for numerous bombings in Russia, and later most of the harm that was done within the U.S. during Day 5. It was precisely the kind of organization which the American-Russian anti-terrorism accord of Day 5 was designed to combat.
Before Day 5
With help from Russian Consul Anatoly Markov, Dawn Brigade leaders made contact with several powerful Americans. The Americans, including James Nathanson and Walt Cummings, brokered a deal to sell the Dawn Brigade twenty canisters of Sentox VX nerve gas. The separatists believed they would be free to use the gas to turn Moscow "into a graveyard".
The Dawn Brigade separatists were unaware at first of a deeper level of the conspiracy. Other powerful Americans (including Christopher Henderson, President Charles Logan, Graem Bauer, Phillip Bauer and Alan Wilson) arranged with the lower-level conspirators (including Walt Cummings and James Nathanson) to have the nerve gas be dispersed by satellite trigger while stored at the Dawn Brigade headquarters in central Asia. The conspirators ultimately planned to kill the separatists, not to support them. Furthermore, the verifiable fact that the Dawn Brigade had the gas in the first place would have been used as an excuse to increase military activity in the region, consequently giving Americans access to more oil.
American conspirator Schaeffer leaked information to Dawn Brigade commander, Ivan Erwich, about the location of the gas canisters, which were hidden in a shelter at the Ontario Airport. Erwich, along with Andrei, Komar, and a fourth separatist, were assigned to move the canisters from their location at the airport to an overseas shipping container, destined ultimately for their base of operations in central Asia.
To cover up the transferral of the gas canisters, another Dawn Brigade commander, Anton Beresch, staged a terrorist takeover of the airport. He began to execute hostages in order to coerce President Charles Logan to refrain from signing an anti-terrorism accord with Russian President Yuri Suvarov. Though Beresch committed suicide, his men were killed by a CTU SWAT team, and the hostages were rescued with help from Jack Bauer, Erwich escaped with the gas.
Erwich personally observed Schaeffer on his way out of the shipping container, and suspected that the Americans had other intentions for the gas. He discovered that Schaeffer had tampered with the trigger mechanisms, and killed him for his betrayal. Erwich was now aware that his former U.S. associates were working against his cause all along. He then sent Komar and Polakov to test some of the gas on American civilians at the Sunrise Hills Shopping Mall. Jack Bauer (undercover as Jacob Rossler) minimized the fatalities at the mall.
The financier and leader of the Dawn Brigade, Vladimir Bierko, killed Erwich for being duped by the Americans and for wasting some of the limited gas at the shopping mall. He then eliminated Nathanson and his associates. Bierko's primary target was President Suvarov, so he forced President Logan to give up Suvarov's motorcade route. The attack on the motorcade failed, so, like Erwich immediately before him, Bierko decided to strike at Russia's new ally: the U.S.
While Bierko's man Viktor Grigorin distracted CTU during a failed attempt to gas a hospital, another separatist, Ostroff, carried out the primary attack and successfully gassed the CTU LA building. About 40% of the staff was killed, and among the fatalities were Edgar Stiles and Lynn McGill.
Bierko then brought all but one of the remaining canisters to the Wilshire Gas Company distribution center. He planned release the gas into the pipes and kill thousands of Americans who happened to turn on their natural gas. Jack and CTU agents intervened, and the gas was incinerated before it left the distribution center.
With help from his infiltrator separatist, Vladimir Bierko escaped from his prison escort and accessed the last nerve gas container. He and his final cell used the gas to board the Russian sub Natalia, and prepared to fire its cruise missiles at various American cities. Jack, with help from Christopher Henderson, stopped them, and what remained of the Dawn Brigade in the U.S. was rendered powerless.