The episode begins with Mayor Goodway, Mr. Porter, Ryder, and the pups watching a video of last year's Tallest and Tastiest Cake Competition, which was won by Mayor Goodway's arch-rival, Mayor Humdinger of Foggy Bottom. This year, Mr. Porter is representing Adventure Bay in the competition, but when he hears that his entry has to be to the City Hall by lunchtime, he races back to his restaurant in a panic at what little time he has to get the cake done. Marshall and Rubble offer to help and lick the bowl afterwards, but Mr. Porter is too busy now to give them that chance as he is busy enough getting all the cakes baked and building the cake one brick at a time. It turns out his cake for the competition is one styled after the PAW Patrol's Lookout tower. They need 1,000 cake bricks, but Alex, despite his attempts to help his grandfather, has only made three, due to being distracted by his toy cars and racetrack.
Suddenly, Marshall smells smoke, and Mr. Porter realizes his cakes are burning. Marshall attempts to extinguish the blaze, but only soaks Mr. Porter, who holds the trays of his two burnt cakes and realizes this puts him severely behind as he now has to re-bake the burnt cakes and needs more ingredients. Seeing Mr. Porter needs help, Marshall and Rubble suggest calling Ryder and the other pups for assistance. Mr. Porter does so, and Ryder summons the pups to the Lookout. Marshall is still holding the carton of eggs he was given in his mouth, and ends up having the eggs fall out and into his mouth, forcing him to unintentionally spit them into the elevator and splatter them over the elevator walls and the other pups.
For once, none of the pups laugh at Marshall's goof-up, and only groan at his egg-related joke about his accident. Once in the tower, Ryder gives the pups their orders, and the pups deploy to help Mr. Porter. When they arrive, they get right to work. Despite Marshall accidentally covering Mr. Porter in cake batter, with the pups' help, the cake is baked and finished, but Mr. Porter is delayed again when Rubble trips on Alex's toy cars and spills the icing on Marshall. Alex apologizes for not cleaning up his toys, but his grandfather is not angry with him, knowing it was an accident. However, he is still upset that they must make more frosting, but when Ryder tells him it will be finished in time if they all pitch in, then he cheers up.
With the pups and Alex's help, the Lookout cake is still iced and fully completed in time to be delivered to the City Hall, but Marshall realizes it doesn't have a slide. With time critical, they have to go without one, but due to the cake being top-heavy, they are pressed with finding a way to stabilize it so it doesn't fall over. Alex offers his toy cars' racetrack as a means to help, and with the track, the cake now has a slide and is stable.
Meanwhile, during the contest, Cap'n Turbot has made a fish cake (yes, out of real fish), much to the disgust of the judge, but the pleasure of Cali. There is also a lighthouse cake, but it's unknown if that is his or not. The judge then tastes Mayor Humdinger's balloon cake, but because there were only the three, Mayor Humdinger is sure that his will win as before.
With Chase providing police escort in front, and Rocky carrying the cake on his truck's forklift, they barely make it to City Hall before the buzzer sounds, ending submissions to the contest, much to Mayor Humdinger's annoyance that Adventure Bay still got an entry in at the last second.
As everyone waits to see the judge's decision, he measures Mr. Porter's cake to be taller than Mayor Humdinger's and, upon tasting it, also declares it the tastiest, and thus the winner, much to Mayor Humdinger's shock. Mayor Goodway and the others are proud of Mr. Porter, and Mr. Porter decides that now all that is left is for the pups to enjoy his cake, since they did another great job.
While the pups enjoy their cake, Cali develops a tummy-ache from eating too much of Cap'n Turbot's fish cake. Marshall gives the PAW Patrol a good laugh to end the episode when he accidentally bumps the table the Lookout cake is on, and the top of the cake falls off on his head, leaving him to eat out the part in front of his face, and Ryder to joke that Marshall really takes the cake.