Secretary of Defense James Heller and his daughter, Audrey Raines, were kidnapped and held hostage by terrorists, who flooded the internet with a broadcast of Secretary Heller's "trial" for what they called "crimes against humanity." Although CTU didn't realize it at the time, the internet broadcast was actually a distraction for the terrorists to use the internet to hack through the safeguards and firewalls of 17 U.S. nuclear power plant computer systems.
When Secretary Heller and Audrey were rescued, CTU agents found an empty briefcase with a logo that led them to a defense contractor, McLennen-Forster. Jack Bauer spoke with someone from the company who explained that the briefcase contained something called the Dobson Override device, which could override a nuclear power plant in the case of a disaster. This device could also do the opposite—create a meltdown.
After Habib Marwan stole the Dobson Override and initiated a meltdown of the 17 nuclear power plants, Edgar Stiles found a piece of code that allowed him to prevent the meltdowns by breaking the Override's control on some of the reactors. He successfully shut down all but 6 of the reactors, one of them being the reactor at San Gabriel Island.
Less than 2 hours later, the reactor at the San Gabriel Island plant began to melt down. Derek Rosner, an engineer, called CTU Los Angeles via videophone and told them that the radiation levels in the plant were at 500 rem, 10,000 times the dose of an x-ray. He warned that the radiation would soon spill into the atmosphere and continue to spread until the plant's core exhausted itself. When Rosner told Secretary Heller about the meltdown, Heller told him to get out of there; but Rosner told him it was too late, as all the people in the plant at the time of meltdown were dying or already dead, all due to radiation exposure.
The maximum potential death count was estimated to be 50,000 persons. CTU continued coordinating the evacuation from San Gabriel Island. CTU also continued to search for Marwan and the Dobson Override in order to stop the other 5 plants from going critical.
Background information and notes
- The actual number of fatalities caused by Marwan's nuclear meltdown on San Gabriel island was never stated. And, although the evacuation of the island was underway, nothing further was clarified about the evacuation's effectiveness. The only information given was an early estimate of the maximum potential death count: 50,000 persons. If the death toll came anywhere close to this number, it would easily make Marwan the most successful mass murderer on American soil in 24. One of the masterminds of Season 6, Abu Fayed, has the most confirmed kills on US soil: at least 13,000. Internationally, Season 7 villain General Benjamin Juma has around 300,000 deaths attributed to him.