Ryder helps Mayor Goodway sort through the old cabin of Outlaw Wild Wilbur when they come across a map for buried treasure. That treasure would be a fabulous addition to the Adventure Bay museum! Mayor Humdinger has other plans; he snatches the map and runs off to find the loot to build his own museum. Spy Chase's drone is launched to find the Mayor and pups track him through the forest. In his haste to beat the PAW Patrol, Mayor Humdinger travels across a dangerous old bridge, it collapses and he finds himself dangling over a deep canyon. Ryder calls in Everest and her grappling hook and the pups save Mayor Humdinger! As soon as he's back on solid ground, Humdinger takes off for the loot - again!
While Rubble and Chase enjoy a game of horseshoes with Marshall attempting to play as well, Ryder is helping Mayor Goodway with attempting to find the lost treasure of famous Wild West outlaw, Wild Wilbur, to add to the Adventure Bay museum at City Hall.
Just as Ryder is checking out Wild Wilbur's old cabin, who should show up with the intent to add Wild Wilbur's treasure to his own museum, but Mayor Humdinger himself. Despite some honesty from Goodway about Foggy Bottom not having a museum yet that Humdinger attempts a good excuse to counter with, Ryder soon finds a map that Wild Wilbur left behind that leads to the location of his treasure. Both mayors are amazed by it, and Humdinger takes out his cellphone to take a picture of it, before he quickly scampers off to try to get to the treasure before Goodway and Ryder can get to it. Ryder takes a picture of the map himself with the pup-pad before summoning the pups to the Lookout.
As Marshall crashes into the elevator, the red horseshoe he was using for the game earlier ends up around his tail, leading him to joke that he got a ringer, much to the other pups' amusement and laughter. Once topside, Ryder tells the pups that they need to hurry to reach the treasure before Humdinger since he has a head start on them. Ryder has Chase come along to deploy his UAV spy drone to follow Humdinger and keep them posted on his location, and Rubble to help dig up the treasure when they find it. The team deploys, and heads after Humdinger.
Once the team reaches where the road ends and they have to go on foot, Chase deploys his drone, and the team begins to follow the map. The first landmark is a tree that looks like an elephant. The next landmark is a river that they need to cross. At that point, they catch up to Humdinger, but he is already across and drags the log over to his side, preventing the team from following. Chase is able to use his zipline to cross over the river and push the log back down so Rubble and Ryder can cross, and the chase resumes. Reaching the next landmark, Snowman's Rock, the map says to take the left fork. Soon after, the team catches up to Humdinger again, just as he starts to cross a rickety old rope bridge and tries to swat away Chase's drone. After breaking one plank loose and into the water below, Humdinger tries to stabilize the bridge, but one of the anchor posts on the side he stepped onto the bridge from breaks, causing the bridge to turn sideways as it loses support on one side, and leaving Mayor Humdinger hanging for dear life onto the remaining, intact support rope.
With Chase's net in his Super Spy Pup Pack unable to reach that far, Ryder summons Everest to use her grappling hook to save Humdinger. She is able to pull him back to their cliff edge, where Chase can then use his net to catch the Mayor and pull him to safety with Ryder, Rubble, and Everest's help. Humdinger is grateful for their assistance, but quickly loses his humility for them saving him as he takes off once more to get to Wild Wilbur's treasure before they can. Luckily for the team, Everest knows the area well, and they are able to reach the end of the trail before Humdinger.
Arriving at where two trees cross to form an "X" together, they find the cave, where another "X" made from stones confirms where the treasure is. Rubble gets to work and digs up one chest, but as he finds another one underneath, Humdinger arrives to take the first one with the old "Finders Keepers, Losers Weepers" taunt. However, once outside, he's shocked to find the chest full of old, red, long underwear that was worn on cold nights in the Wild West. Although Ryder assures him that it is still valuable, Humdinger surrenders it to them in disgust and walks away grumbling and muttering to himself at the thought of having been sent on a wild goose chase for clothing. With Humdinger gone, Ryder and the pups dig up the second chest, and find that one full of coins, proving that there was treasure after all! Wild Wilbur must've buried his underwear on top of the coins as a decoy to throw off would be thieves.
Back at Adventure Bay's City Hall, Ryder and the pups present the two chests to Mayor Goodway, who's very grateful at this new addition to the museum. Humdinger soon shows up to discover that there was real treasure after all, but with the chests now property of Adventure Bay, Humdinger finds himself as the "Losers Weepers" part of the taunt he gave the PAW Patrol earlier. As Humdinger sulks on the steps of City Hall, Chase and Everest enjoy themselves in wearing some long underwear just their sizes. However, when one coin from the chest filled with them happens to roll out and land near Humdinger, he attempts to greedily grab it so he can still walk away with some piece of Wild Wilbur's treasure, but Chickaletta quickly snatches it. Humdinger cries at the end. Ryder commends Chickaleta and the pups for being a good chicken and pups. The PAW Patrol laugh, ending the episode