Skye and Marshall help Cap'n Turbot plan a special celebration for Wally the Walrus, only Wally is a no show! Zuma dives in to search for him underwater while Skye goes up high to scan the bay. When they find Wally, he's not alone, he's got a special friend, Walinda! Things get even more exciting when the gang discover that Wally and Walinda are going to have a baby. The walruses jump and flip around celebrating and as Walinda dives down deep she suddenly gets tangled in an anchor chain. She needs to be rescued! And before you know it a baby walrus pup is the newest addition to Adventure Bay.
As the episode opens, Cap'n Turbot is loading his van full of fish-related treats, like jellyfish jelly and stinky squid jerky, to give to Wally for Walrus Appreciation Day. After he leaves, Marshall deals with a seagull that is attracted to the jelly covering his tail.
Out at sea on the Flounder, Turbot is worried as Wally has not shown up yet to feast on any of the treats he set out. Concerned, he calls Ryder to let him know and ask him to come out and look for him. Ryder agrees and summons the pups. When Marshall crashes into the elevator, the seagull nearly walks off with his fire helmet before he retrieves it and gives the pups a laugh as he tosses it back onto his head upside-down. Once topside, Ryder has Skye and Zuma assist in looking for Wally. The team deploys, Ryder activates his life jacket, and they head out to meet up with the Captain.
Once there, Skye attempts to lure Wally out with a bucket full of treats and squid jerky, although she, Ryder, and Zuma, are still sickened and disgusted by the smell. She soon spots several piles of spent oyster shells on the beach below the Lookout. Thinking Wally might be nearby, Ryder and Zuma head over with another bucket full of smelly squid jerky. Along the way, several seagulls attempt to eat the payload, but Ryder and Zuma are able to shake off all but one, who stubbornly refuses to let the squid jerky escape, and manages to down a couple of pieces before it looks as though Ryder spooked him off. Turns out, it was Wally who did it.
When Ryder offers a piece of the jerky to Wally, he lets it bounce off his head to be eaten by a purple, female walrus. Upon seeing that, Ryder tells Turbot, and upon returning to the Flounder, Turbot names the female walrus "Walinda". When Turbot offers some of the cookies to Wally and Walinda, surprise! Walinda is pregnant with her and Wally's first child, and Wally is giving her all the food to help with her pregnancy. However, when Wally and Walinda dive underwater so Walinda can chase a tasty fish, Walinda gets her tail snagged in the anchor chain of a buoy marker. Once Turbot figures it out, Ryder puts on his scuba gear and dives under with Zuma and Wally to free her.
At first, Walinda refuses to let them help free her as she continues to struggle to pull her tail loose herself, but once Ryder gives her something to munch on, she calms down long enough for them to free her. They succeed, but Walinda is tired out from wasting so much energy trying to escape herself. As a result, Zuma helps her to the surface, and Wally takes her to shore to recuperate.
A week later, the pups and Ryder come to check up on Wally and Walinda. Turbot has not seen them at all the past week, but his concern is put aside when Wally and Walinda appear and reveal that Walinda has given birth to her and Wally's new baby walrus. The team celebrate by giving Wally's new family some treats and squid jerky, but when Marshall eats the treat he was trying to toss to the walrus family, he finds that is tastes better than he thought. Turns out, Turbot ran out of fish snacks and is using fish-shaped dog biscuits instead. Each of the pups get one, and even Turbot tries one himself, leading to a round of laughs from everyone as he quotes himself from "Pups and the Very Big Baby": "That's some marvelous munchies!" to end the episode.