"Pups Save a Lost Tooth" is the second segment of the 4th episode in Season 3 of PAW Patrol.
The pups' boat ride with Cap'n Turbot is postponed when they must track down a lost tooth.
Alex Porter and his grandfather are on the playground as Alex enjoys a nice swing before showing that he still has his loose tooth intact. His grandfather offers him a nice carrot to eat, and when Alex bites down on it, his tooth comes out and ends up embedded in the carrot. As Alex shows his grandfather what happened, they leave the carrot and the backpack on the merry-go-round, where another kid ends up spinning it around so much that the carrot ends up on the see-saw, but when Alex and his grandfather return and find the carrot missing, they become worried and call Ryder.
Once Ryder gets the call, he was about to take the pups on a trip with Cap'n Turbot to feed the dolphins, but seeing that duty called, the Captain is okay with Ryder dealing with helping Alex first. Ryder summons the pups, and as Marshall responds, he notices Rubble still asleep, and helps him into the elevator, though due to riding in on Rubble's skateboard, Rubble thinks he just had the most amazing skateboard dream as a result. The team head topside and receive their orders: Rocky will come and help look for the carrot on the playground while Chase tries to find it with his spy drone UAV.
The team head out, and once at the playground, get to work. Rocky manages to find Alex's Apollo the Super-Pup action figure, before then finding an old lollipop in the bushes. Chase's drone has better luck as it locates a carrot a little girl is eating, but annoys her mother in the process before Chase calls it off, then finds the right one on the see-saw. Before they can retrieve it, what follows after is basically a game of "Keep Away" as the carrot keeps being out of reach by Ryder, Alex, and the pups.
The carrot is sent flying into a tree, stolen by a crow to give to its chick, which spits it out so it falls in a passing trailer carrying Bettina, swatted by Bettina's tail, then bouncing across a few things before finally landing in one of the buckets of fish that Cap'n Turbot was taking on The Flounder to feed the dolphins. As Ryder prepares to hit the water, he deploys his lifejacket, and when Alex tries the same thing, Ryder deploys one for him as well, before converting his ATV to hovercraft mode. Unfortunately, when Ryder explain the situation to Cap'n Turbot about the carrot, the dolphins, none too happy at being denied some fish, tackle the Captain overboard and knock the bucket out of his hands. After Ryder and Alex help the Captain back aboard The Flounder, they realize they will have to go underwater to find it and call Zuma.
Just after Zuma arrives, Alex spots the bucket bobbing on the surface, only to then be lifted into the air by the playful and mischievous Baby Whale. When the whale refuses to give it back, Ryder suggests Zuma use his buoy, but after Zuma is able to retrieve the bucket, the Baby Whale surfaces right under him to send him and the bucket flying, but thankfully, Ryder catches them both.
Back on shore, Mr. Porter retrieves the carrot, and returns it to Alex, who is so happy that he nearly loses it again, before Ryder catches it and returns it to him.
The next day, the pups get their chance to feed the dolphins with Cap'n Turbot. Alex arrives to reveal the new ball he got from the Tooth Fairy, only for the dolphins to take it and lead to where it ends up going back along the path the carrot took previously in staying out of reach, leading Ryder to take the pups and get it back as Alex watches them go with a laugh and cheer.