It started with the pups playing tug-of-war, Chase, Zuma and Skye vs. Marshall, Rubble and Rocky. As Marshall's team was about to win, a butterfly landed on Marshall's nose, tickling and causing him to let go of the rope, letting Chase's team win. Rubble asks for a rematch and all the pups said "yes."
Meanwhile in the Dino Wilds, Taylor Turbot, Rex, and Benny were also playing tug-of-war, Taylor vs. Rex and Benny. Rex and Benny win and Taylor would let Benny on her team next time. Then suddenly, they heard a rumble coming from somewhere. Dr. Turbot had discovered a volcano about to erupt. The dinosaurs near it will get hurt and burned if it erupts. They need help to get the dinosaurs to safety, so Taylor began to call the PAW Patrol.
Back at the Lookout, before the pups could play the next round of tug-of-war, Ryder got the call from Rex and the Turbots. They told him about the volcano erupting soon and that the dinosaurs need to move away from it. Ryder told them that they're on their way, as he summons the pups to the Dino Patroller. They entered the tunnel, pass the waterfall, and reached the Dino Tower, where Rex was waiting. As everyone got geared up, Ryder told the pups about the volcano about to erupt, and the dinosaurs near it. Their mission is to get the dinos safe from the eruption. Ryder hired Chase to get the dinos' attention and get them away the volcano, and Rex to help Chase herd the dinos and tell them they need to go. He also need all pups to help out. As everyone was ready, they hopped into their vehicles, and off they go to save the dinosaurs from the volcano.
The volcano was getting close to erupt, and the dinosaurs are still near it. The PAW Patrol made it, and Chase and Rex warned the dinos to move away from the volcano. The dinosaurs listened and followed Rex away from the volcano, but a baby triceratops and a baby velociraptor were playing tug-of-war with a stick. The mom triceratops told them to stop, but the baby triceratops accidentally threw the baby velociraptor on the ledge of the volcano. As they saw the whole thing, Ryder asked Skye to help the baby raptor down. Skye asked the baby to stay still while she gets him hooked up. The volcano rumbles again, causing the baby to fall off. But luckily, Skye caught it on time.
The volcano bursts a ball of lava out and landed on the grass, the eruption is about to begin. Rex explained that the grass around the volcano is the dinosaurs favorite place to eat. Ryder told the pups to keep the dinosaurs moving away, and hired Marshall to put out the lava before it burns anymore grass. Marshall put out the lava, but the volcano is still going to erupt. Ryder hired Rubble to dig a trench so the lava can go in the canyon.
As Ryder caught up with the pups to keep the dinosaurs moving, Chase saw a baby stegosaurus not moving. Rex told it to come with them get away from the eruption. The baby obeyed and hopped onto Chase's dino-car. As they were still moving the dinosaurs away, Rubble was still digging the trench. They were almost away, they had to get across the rock bridge. But, the rumble from the volcano cause the bridge to collapse and some trees to fall and block the way out. Ryder asks Rocky, Zuma, and Skye to take the fallen trees and pile them up, so the dinosaurs can cross safely. Rocky used his truck's lift plates to move them, Zuma pulled them with his vehicle's winch, and Skye used them to make a new bridge. Now that the bridge is done, the dinosaurs made it across.
As for Marshall and Rubble, Rubble was done digging the trench, and they both saw that it worked, the lava had entered the canyon. The dinosaurs were safe away from the volcano, but it's still erupting. A Tyrannosaurus Rex was stuck on the other side of the river of lava. As the PAW Patrol saw him, they needed to do something to help him. Ryder called for Robo-Dog to bring the Dino Patroller, and ask Rex to help get him onboard. Robo-Dog arrived as Ryder and Rex boarded. Ryder asked Rubble to help them get across the lava.
They drove across the bridge and made it to the river of lava. Rex warned Ryder that the Dino Patroller can't drive through the lava. Ryder thought it through and came with an idea of how to get across. He asked Rubble to push some big boulders into the lava to make a bridge, so they could get across. Rubble started putting in big rocks into the lava, and a few minutes later, he was done. Robo-Dog drove over the boulders and they made it the T-Rex. Rex told him to follow him to the Dino Patroller so they could get him out of the volcano area. The T-Rex trusts him and boarded the Dino Patroller. Before they could get across again, the lava had cause the boulders to float down. Ryder had found a rocky ramp and decided to use it to sling themselves over the lava. Robo-Dog drove as fast as he could and they made it to the other side of the lava, and the T-Rex started to run away by himself from the volcano.
After the mission is complete, the volcano stops rumbling and erupting, finally safe enough for the dinosaurs to have their favorite food. The baby stegosaurus walked in front of Ryder and jumped into his arms, saying "thank you." And Ryder said, Whenever you need to move a bunch of dinosaurs, just yelp for help."