Three dogs endure a brutal sea storm as their father, Captain Dogwood, Garry Chalk, stays aboard his ship and sends the pups to a lifeboat to ride out the night. By dawn, Salty the Seagull and Echo the Dolphin, Kathleen Barr, spot the pups and bring them onto the deck. The young dogs introduce themselves as Andy and Tina, and Echo sets out to locate their father.
Salty agrees to help find Captain Dogwood because he knows him well. The only way to reach him is with Little Toot, a tugboat that used to be the busiest and proudest vessel in the harbor, until boats no longer needed him and he slid into dirt and disrepair. Now he’s a handy home for three cats, who seem determined to make life miserable for everyone around him.
To reach Dogwood, the group hatches a plan to scare the cats away from Toot, since cats famously fear dogs. At first the cats are petrified, but once they realize the danger comes from puppies and not grown dogs, they regain their nerve. The pups want the cats off Toot for good, but the cats refuse, insisting they need him to collect a shipment of sardines Dogwood was delivering. They even threaten to throw the pups overboard and feed them to a shark, until Salty inspires Toot to stand firm and shoo the cats away. Toot blasts the cats with his hose, because—like many creatures—cats hate water. The plan works, the cats flee, and the crew begins to scrub Toot back into shipshape condition.
Echo returns with news that Dogwood is shipwrecked on an island. Salty heads off to grab his favorite snack, Percy’s Perfect Purple Pickle Pelican Pellets, while the others collect bubble gum and ice cream for the journey. As Little Toot chugs away again, the cat leader Claws, Alec Willows, vows to use him to find all the sardines he and his coterie crave.
Their voyage carries them to a new encounter with Typhoon Tessie, the weather lady, Gwyneth Harvey. She proclaims that she knows what happened to Dogwood because it’s her job to create the weather and she must have her job to keep the world changing. She warns that her winds and storms will continue unless they accept that meteorology is her domain. A fierce storm erupts, and the crew must press through the maelstrom while the cats try to reach Toot, a challenge made tougher by the raging weather. Still, Toot hears their cries and heads back to lend a hand.
As Salty points out they’re heading toward Skull Rocks, the cats beg to return to their own boat, only for it to sink beneath the waves. Echo calls out to Toot to ride the surf, and the rampaging sea calms just in time for them to reach safety. The pups celebrate Toot’s bravery, and Salty orders the cats to help tidy Toot up, much to their chagrin.
They reach the island and find Dogwood’s ship partly wrecked but still afloat. Salty and the pups head out to search for Dogwood, while Toot dozes. The cats seize a moment to tie the captain’s ship to Toot, hoping there are sardines hidden in the kitchen. They soon discover Dogwood wakes up, relieved and overjoyed to see his kids and Salty.
Then a volcanic eruption erupts in the distance, forcing the group to board Toot and sail away. The cats manage to tie the two vessels together and be pulled along, while lava blocks their path. Toot comes up with a wild plan: he packs his mouth with bubblegum and blows a humongous bubble that carries them over the molten flow. They land safely on the other side and share a moment of relief and triumph.
Back on the open water, the crew congratulates Little Toot and reassures him that there’s plenty more to do, a promise he accepts with a renewed sense of purpose, declaring he will never feel sorry for himself again. The cats, meanwhile, comb the ship in search of sardines, only to learn that Dogwood had tossed them overboard to lighten the load, much to their dismay. Salty’s insistence on keeping his pickle stash becomes a running joke—he objects at first, then breaks into a laugh that spreads through the crew. With the tension eased and the laughs rolling, everyone heads back toward the harbor, ready for whatever adventures lie ahead.
