It's Alex's first day of school, but he has lost his backpack! So the PAW Patrol agrees to help him find it. Easier said than done when Alex says that his backpack could be in many places around Adventure Bay, prompting all the pups to be deployed to all corners of the city, not to mention they have limited time before the school bus arrives. Can the PAW Patrol get the backpack before the school bus picks Alex up?
The episode starts with the PAW Patrol waking and enjoying some yoga before breakfast. Chase is leading the session, but Marshall is still tired, and yawns his way through before finally going back to sleep, earning a laugh from the other pups as Rocky announces that he's doing the "snoring dog".
Meanwhile, at Mr. Porter's, Alex is getting ready for his first day of school, but there's a problem: His brand-new red backpack is missing. Fearing he is now unable to go board the school bus when it arrives, Alex calls Ryder for help, just as Ryder was about to give the pups breakfast. Once Alex asks the PAW Patrol to help him find his backpack, Ryder agrees and calls the pups.
Once topside, the pups feel sorry for Alex when they learn of his plight. Ryder decides to have Chase accompany him to interview Alex on his backpack's last known whereabouts, while Skye will trail the school bus, and relay the location of it back to Ryder. With that, the PAW Patrol deploy, and Skye soon has the school bus in her sights, busy picking up kids in the residential area on Hill Street.
At Mr. Porter's, Alex does his best to retrace his steps on where he had his backpack last, but due to how he had it in numerous places around Adventure Bay, Ryder and Chase remain at the restaurant to continue getting details, while Ryder dispatches the other pups to check the locations Alex mentioned.
First off, Marshall heads to the park to look there, but only finds a red balloon stuck in a tree with the aid of his gosling friend, Fuzzy.
At the beach, Zuma only finds an old, red life jacket that he takes from Wally the Walrus to help clean up the bay, thanking Wally for his help.
Rubble tries Farmer Yumi's, but only finds one of her red bandannas under some hay bales.
Rocky's attempt at City Hall only results in him accidentally taking Mayor Goodway's red purse off her shoulder, causing her to fall over, and Rocky to apologize to her, and Chickaletta when she springs up out of the purse.
With the school bus now heading down Main Street towards Mr. Porter's, Alex's latest memory recall mentions that he had his backpack at the train station. Ryder and Chase hurry over, and spot the backpack hanging from the railing on the caboose of the train. As they approach, the backpack starts to move about, and a familiar grey tail pokes out of the top of the backpack with a curious, muffled meow. Thanks to his allergies, it doesn't take Chase long to figure out that it's Cali, attracted to the tuna fish sandwich Alex was going to have for lunch at school.
However, the train starts to depart, and with Cali now trapped in the backpack, getting a free ride down the rails, Ryder calls Skye to airlift him after the train to get Cali and the backpack back. While Ryder goes after Cali and Alex's backpack, back at Mr. Porter's, with the school bus now about to arrive to pick Alex up, Alex is disheartened by being unable to take his backpack to school, and apologizes to his grandfather for losing it. Back at the train, Ryder is soon swung close enough to retrieve the backpack, and while Cali scurries onto Ryder's back for safety, Skye carries them both back to Mr. Porter's.
Alex is just about to board the school bus when Ryder returns and drops him his backpack. Alex is so happy that he has his backpack for school again, and thanks Ryder for his help. Ryder never even gets a chance to finish saying the PAW Patrol motto before Skye airlifts him to head back to the Lookout. Alex soon notices that someone ate his tuna fish sandwich, and while Cali lets off a giggle as being the culprit, Alex waves goodbye to his grandfather as the school bus departs, and Mr. Porter wishes his grandson a great first day of school.
Back at the Lookout, the pups are ready to eat, and Ryder is quick to feed all of them. Once the pups are digging in to their food, Ryder hears a meow, and turns to find Cali having joined the pups, wanting some breakfast as well. Ryder doesn't forget her, and gives her a tuna fish sandwich. As Cali joins the pups in digging into their breakfast, the episode ends with Ryder laughing as the pups and Cali enjoys their food.