A seismologist from Los Angeles warns of an imminent earthquake, of a magnitude never known before, more than 12 on the scale. An earthquake of that scale means the total destruction of the city and the loss of thousands of lives.
What happens is that this seismologist is discredited by some events that happened in the past, which means that no one takes their predictions seriously. She does her best to take them into account, but when she sees that no one is going to ignore her, she sets to work to try to save her family.
On the tape we will see her desperate attempts to save her entire family, just before all the continental crust on which the city of Los Angeles sits, is destroyed by the earthquake that she herself has predicted.
If you can not save the city, at least try to save the people you love the most.