Arriving at the next port located on Ascorbia Island, Ash and his friends are eager to get something to eat. However, their plans are shelved when they approach a warehouse on fire. Defying Officer Jenny's orders, Ash and Misty rush towards the inferno. They send out Squirtle and Staryu to douse the flames, but their efforts are in vain, as the fire begins to spread. Just when some debris begins to fall on the group, a team of Wartortle appear to save them. With a blow of a whistle, they proceed to douse the flames in a coordinated display. Still, Squirtle is not pleased and focuses much of its attention on the lead Wartortle, which wears a yellow bandana around its neck.
Later that day, the team's Trainer, Captain Aidan, introduces Ash and his friends to his firefighting force: Teams Squirtle, Wartortle, and Blastoise. Team Blastoise is used for large-scale fires, Team Squirtle for tight-space rescues, while Team Wartortle is used in more general-purpose scenarios. Ash notices Squirtle's discontent, and is even more shocked when it puts on its signature black shades. Tracey is initially confused, but Ash details Squirtle's past as part of the troublesome Squirtle Squad. Ash quickly notices Squirtle's attention to the proceedings, and quickly realizes that its firefighting confidence had been shot when Squirtle itself had to be rescued. Ash begs Captain Aidan to have Squirtle join Team Wartortle for a day of training, which Captain Aidan reluctantly accepts.
Squirtle proves to be every bit as capable as the head of Team Wartortle. In a running exercise, the two are able to outpace the rest of the team. Even though Squirtle had tripped over a pebble and rolled its way to the finish, it set a new land speed record for a Turtle Pokémon. In a shooting exercise, Squirtle and Wartortle are able to shoot down moving targets with equal precision. However, one rogue target leads the team astray from Captain Aidan, and the team soon finds themselves falling into Team Rocket's pitfall trap. Team Rocket emerges from the crater in their Meowth Balloon with Team Wartortle and Ash's Squirtle ensnared in a net. They perform their motto, and with a pair of mechanical hands, Meowth snatches Pikachu as well. Weezing uses Smokescreen, allowing Team Rocket to escape. Tracey sends out his Scyther to clear the air, leaving the Pokemon exhausted.
Later, Team Rocket lands at a log cabin, using Pikachu's electricity to power a fan while the trio admires their loot. Jessie and James then begin arguing over who should keep one of the Wartortle, while Meowth tries to bribe the Turtle Pokemon with food. Jessie interrupts, but Meowth scratches his teammates' faces. Unbeknownst to them, Squirtle comes up with a plan and discusses it with Wartortle.
While busy looking for Team Rocket, Captain Aidan receives a call alerting him to an apartment fire. Jenny explains that an overturned truck has delayed Team Blastoise, and while Team Squirtle is on the scene, they are easily overwhelmed. At a loss and without Team Wartortle, Misty offers Staryu as a stopgap measure, and Tracey sends out Marill and Scyther to help out. Meanwhile, Venonat continues to search for the missing Pokémon and soon spots the Meowth Balloon.
Inside, Team Rocket is still fighting amongst themselves when Squirtle and Team Wartortle flood Team Rocket's cabin with water, with the pressure bursting the doors open. While Team Rocket is washed out of the building, Squirtle and Wartortle remain trapped in their nets, but manage to bunny-hop over each other to slowly inch their way out of the cabin. Now outside, they lure Meowth into having him scratch them free from their net, as they withdraw into their shells to avoid getting hurt. Just then, Ash and Captain Aidan arrive on the scene, and Venonat Tackles Team Rocket out of the way. In a last-ditch effort to claim Squirtle and Team Wartortle, Team Rocket sends out Arbok and Weezing. However, they are propelled backwards by Water Gun, and Pikachu's Thunderbolt sends Team Rocket flying.
At the apartment fire, Misty and Scyther become worn out; while Staryu, Marill, and Team Squirtle are unable to contain the fire. However, Squirtle and Team Wartortle arrive in time, just as a child is revealed to be trapped in the building. Squirtle puts on its black shades and is eager to meet the challenge. It and the head Wartortle, with help from a Blastoise, are propelled into the fiery building. They soon reach the child, and Wartortle has the boy cling onto its back. Unexpectedly, the floor crumbles under Wartortle's weight, but Squirtle manages to pull it and the child back to safety. Wartortle then notices a falling door, and uses Water Gun to save Squirtle from injury. Wartortle and Squirtle emerge with the boy in hand, leaping over a wall of fire in the process. Team Wartortle, Squirtle, and Blastoise's efforts eventually manage to put out the fire. The young boy is reunited with his mother, who then thanks Captain Aidan for his efforts. Ash urges the woman to thank the Pokemon as his Squirtle and the lead Wartortle shake hands. In the end, Ash and his friends part ways with Captain Aidan, but not without performing a final salute.