Scientists make a horrible discovery: The "Big One" is coming in two days, with it, California will sink to the ocean. Their only hope is to rupture a volcano that will displace the earthquake's energy and build a new crust on the surface. But as foreshocks turn California into chaos, it's a race against time the scientists might not win.

　　超级太阳风暴导致的地震及火山喷发，引起了科学家梅雷迪思的关注。她对此十分担忧，并确信近期不断发生的地壳活动，是毁灭性灾难来临前的预兆。情况危急，得不到同事认可的梅雷迪思决心将情况上报给市政府，希望政府重视并对全人类做出警示。然而灾难的到来比梅雷迪思预料的更快，正当她到达市政厅，表明来意欲面见市长之际，海啸、地震、火山喷发等活动正在全球同时爆发，交通瘫痪，通讯中断，城市顷刻间变为人间地狱……

　　Russian operatives hijack a commercial American jet, planning to crash it into a nuclear power plant near Washington, D.C. resulting in fallout that will devastate the Eastern seaboard. With little time for Air Force fighters to shoot it down, the passengers and crew aboard the aircraft must rely on their own military and civilian training to stop the terrorists before it's too late.

　　洛杉矶又受到怪物的袭击，这次袭击的怪物力量远比它们的前辈更为强大，整座城市陷入了恐慌之中，罗素博士临危受死,带领着冲锋队奋起迎战。

　　一颗巨型小行星威胁说，在旨在阻止撞击的军事协议失败后，它有可能摧毁地球。

　　ABC正式宣布续订剧集《19号消防局》。