In the 911 season 10 premiere, the 118 got right back into the thick of things as a sinkhole opened up in Los Angeles and a number of striking calls related to something being wrong with the city's water. By the end of the episode, Maddie discovered a staggering connection between the vast number of calls, just in time for a volcano to erupt with lava in the sinkhole.
911 season 10 episode 2 opens with news overage of the sinkhole volcano and scientific explanations for why it's happening. The city is urging residents to evacuate since lava will soon begin flowing. The 118 is on the scene, and Chimney speaks directly to Maddie about getting the situation organized. As the volcano erupts again, the team ducks under the firetruck.
Traffic has piled up throughout the city, and in the middle of a jam, everyone begins to to rush out of the their cars and run away on foot. It's because lava has begun pooling around the cars. May and her co-worker suddenly become overrun with patients at the hospital from the volcano at the same time the 118 arrives at the "river of lava." Chimney and Maddie come up with a plan.

The 118 and Maddie battle a volcano in Los Angeles
While they wait for additional help, the plan is basically a game of Floor is Lava. Meanwhile underground, Athena hears a voice behind a pile of rubble. She crawls through the other side and finds a man named Harvey and Matthew Sparks (Zach Tinker). An office finds the jewelry store owner on the ground, making the situation ever more interesting.
Back at the river of lava, Chimney tries to keep the people calm, but a man isn't doing well with being patient. Rather than wait for the 118 to help guide him to safety, he jumps from car to car until he falls right into the pit of lava to his death. Everyone learns a lesson from that and allows the 118 to assist them. Maddie alerts Chimney to a nearby car accident and sends Hen and Harry to check it out.
Maddie thankfully gets reinforcements at the call center to help mediate the situation. Still underground, Matthew attempts to apologize to Athena, but she's not particularly having it. He never contacted the woman he shot, but Athena has. Maddie finds herself in the tricky position of making a tough call for mutual aid, which apparently cost $40 million.
Hen and Harry enter the apartment the call was coming from, and they find a woman lying on the ground with her body smushed by a lava ball. Hen instructs Josh to keep the lava ball victim on a list for rescue, and she will ensure that she makes it. Eddie finds a service dog, and the team tries to find its owner. Eddie decides to walk the dog around the cars, using its sense of smell, to find its owner.
Eddie finds the owner, Ryland, inside his car having a seizure. He places the dog inside the car to comfort Ryland as Eddie enters the car for treatment. Athena realizes that they have been walking in circles in the tunnels. She and Matthew realize that Harvey's memory isn't as strong as he thought or they initially believed. He doesn't even recognize Athena.

The lava takes another victim
Athena checks Harvey for a concussion, but she's not sure what's wrong with him. He doesn't remember anything that's going on. While he's coherent, Athena asks him the directions to get them where they're going. He's excited to get out of the tunnels and get home to his wife, but Matthew tells Athena that Harvey's wife died three months ago.
The hospital continues to be overrun with patients, including a bride who brings her new husband in directly from their wedding. He's covered in burns as May begins treatment. Unfortunately, his arm begins shooting blood and the groom starts passing out. May panics and her coworker takes over for her. She excuses herself to another room and sits on the floor to cry.
Hen and Harry continue to treat the woman with the lava ball trapping her body, but her kidneys and liver are beginning to fail. She's realistic that she will likely not survive to make it to surgery or even out of surgery. She refuses any further medical treatment, but Harry doesn't want to give up. Hen agrees to simply keep her comfortable until she passes. Harry stays with her.
Athena almost makes it out of the tunnels
Maddie and her team realize that the situation is continuing to get worse, and she's again saddled with an impossible situation regarding which area of the city to save first. Back at the scene, Buck needs to extract a pregnant woman named Paige from her car and get her to safety. He talks her through multiple jumps from car to car, but they're soon surrounded by flames.
Chimney springs the team to action to save Buck and Paige. Just before an explosion, they're whisked away to safety and her baby's just fine. Hen returns to the scene, but she's downcast. Harry sits with the woman and holds her hand as she tearfully grapples with her impending death. After one final word of wisdom, she dies. Meanwhile, Maddie continues to weigh the options.
Tearfully, she makes a decision, knowing that she looked at every single possibility and tried to make the most informed choice for the city and its residents. While May's doing much better at the hospital, Athena runs into a group of rats before she, Harvey, and Matthew get to their destination. Unfortunately, another explosion thwarts their plans and puts lava right in their path.
911 airs Thursday at 8/7c on ABC and next-day on Hulu.
