A major earthquake caused a volcano deep underground in Los Angeles to erupt, flowing toward residential areas, and workers who were repairing underground pipes were burned to death. When geologist Amy and her friend went down to the tunnel to survey, they personally experienced their friend being taken away by the magma eruption. For a while, a corner of the city was filled with magma erupting underground. Mike (Tommy Lee Jones), the commander-in-chief of the crisis management center, took Dr. Amy's advice and began to evacuate the crowd. They first used millions of tons of air precipitation to turn the raging magma into an obstacle and block the flow of magma. Just when everyone thought they were relieved, Dr. Amy believed that the magma was not really blocked, but just changed its flow direction, and was rushing to the hospital full of injured people. They only have 30 minutes left to deal with this problem. Can they succeed?