10.5 - Seattle, Washington: dawn. An earthquake trembles with a 7.9 magnitude. It's the biggest natural disaster to hit the West Coast in over a century. The aftershock hits Northern California, reaching 8.4, splitting the earth and swallowing a train as it cruises along the landscape. The chance of an aftershock being greater than the quake is virtually unprecedented. Dr. Samantha Hill (Kim Delaney), an expert on hidden fault lines, and the President of the United States (Beau Bridges) must race against time to save the lives of millions. CATEGORY 6 - Nature strikes out with unfathomable fury as the unimaginable becomes a terrifying reality. Three twisters descend upon Las Vegas leaving a neon wasteland in their wake. Hurricanes tear through the Gulf Coast without warning. Record-high temperatures scorch the northeast. One-hundred-mile-an-hour winds tear across the south. Lightning storms ignite the sky. Wildfires blaze out of control. For Amy Harkin, a budding Chicago anchorwoman looking for her big break, the fear of these weather anomalies is second only to the dread of the inevitable repercussions: rolling coast-to-coast blackouts and the dwindling sources needed to revive them. With the worse power breakdown on record looming, an overload could cripple the nation and leave the entire population in the dark, without communication and vulnerable to unthinkable dangers.