Raymond "Ray" Gaines, portrayed by Dwayne Johnson, is an Air Rescue pilot with the Los Angeles Fire Department facing a tough divorce from his estranged wife, Emma, played by Carla Gugino. As he plans a trip to San Francisco with his daughter, Blake, portrayed by Alexandra Daddario, disaster strikes.
Meanwhile, seismologist Lawrence Hayes, played by Paul Giamatti, along with his assistant Dr. Kim Park, is conducting research at Hoover Dam when an unexpected fault line ruptures, unleashing a catastrophic 7.1 magnitude earthquake that damages the dam, leading to Park's tragic demise.
As Ray is summoned for duty in the wake of the disaster, Blake instead goes to San Francisco with Emma's new partner, Daniel Riddick, portrayed by Ioan Gruffudd. Soon, Hayes deduces that the San Andreas Fault is on the verge of a more devastating earthquake. During a lunch outing, Emma experiences the force of a 9.1 magnitude quake that takes the life of Daniel's sister Susan, played by Kylie Minogue. In a heart-pounding moment, Ray saves Emma from a crumbling building, narrowly escaping by helicopter.
In the chaos of San Francisco, Blake, alongside Daniel, encounters Ben, an engineering student played by Hugo Johnstone-Burt, and his brother Ollie, portrayed by Art Parkinson. They attempt to find safety but get stuck in a parking garage as more earthquakes unfold. While Daniel abandons her, Blake teams up with Ben and Ollie, who help her reach a phone to call Ray and Emma for rescue.
Ray’s helicopter suffers mechanical failure, forcing him to land in a shopping mall at Bakersfield, where he commandeers a truck to push through the looting chaos. On their journey, they encounter an elderly couple who offer their plane in exchange for Ray's vehicle, aiding in their quest to reach Blake.
Back in San Francisco, Blake, Ben, and Ollie struggle to send a signal from Coit Tower, which is now ablaze. As Ray and Emma parachute into the city amidst a colossal 9.6 magnitude earthquake—the largest ever recorded—they face overwhelming destruction. In the ensuing turmoil, they persevere despite an imminent tsunami.
The tsunami strikes as the group runs into Daniel's building, which becomes inundated, resulting in Daniel's demise on the Golden Gate Bridge when a cargo ship destroys its span. Evading disaster, Ray and Emma eventually find Blake, Ben, and Ollie amidst the flooding chaos. After a tense moment of uncertainty, Ray manages to revive Blake, leading to a joyful reunion.
They finally arrive at a relief camp where Ray and Emma, now reconciled, discuss their future together as rescue operations begin to unfold across the ravaged San Francisco Bay Area.
