Mitch awakens from a dream in which the old trailboss Curly from the first film, rises from the grave and drags him down. However, Mitch soon forgets the dream when the familiar voice of his Mom comes through the speakerphone, giving her recitation about the events that led to his birth, as today is Mitch's 40th birthday.
Unlike his 39th, Mitch's outlook on life has changed. Going into work, he meets his friend Phil, who Mitch has gotten a job at the station in the wake of Phil's recent divorce. Phil admits he feels lonely in the wake of his divorce, and Mitch invites Phil to his place for his Birthday.
On the train back, Mitch swears he sees Curly on the train, and discusses this with Phil. Phil believes that Mitch is seeing things, since they checked Curly before he was buried, and confirmed he was dead.
When they arrive home, Mitch is shocked to find his younger brother Glen has arrived unexpectedly. Wanting to be alone with his wife, Mitch sends Glen home with Phil, but during the evening, Mitch looks through curly's belongings that he kept, and finds a map inside the old trailboss' hat.
Showing it to Phil the next day, they analyze the map and surmise that it belonged to Curly's father, Lincoln Washburn. Hoping to find the treasure that is mentioned on it, Mitch and Phil head out West, bringing Glen along as well. Using the ruse that they are in Las Vegas, they rent equipment and head out to find the treasure.
Unfortunately, Phil mentioned the treasure to the men who they rented the equipment from, who come after the group for the map. However, this is spoiled when a familiar face shows up! Mitch assumes his thoughts that Curly was not dead are correct, but their savior is Duke, Curly's brother. Duke had come looking for Mitch to get the map and claim his family's treasure.
Mitch and Duke are first at odds with each other, but when Mitch explains to Duke how Curly explained his philosophy about life ('One thing, just one thing'), Duke is willing to let the men in on the treasure as well, provided that Duke gets half and the three of them have to split the other half amongst themselves.
Eventually, the group is caught up in a stampeded, and the map is lost. Things seem grim until Glen tells the others that due to his photographic memory, he recalls the last part of the map's information.
Eventually, the men find the gold, but are then set upon by bandits, who shoot Glen! However, it soon turns out that the bandits are just actors, when a familiar face shows up: Clay Stone, who was in charge of the ranch where Curly worked and where Mitch and his friends went the year before!
Clay then provides the others with copies of a map exactly like what Curly had, claiming that this latest venture had been Curly's idea as a way to attract tourist: lead them on a treasure hunt and then be shot at by fake-bandits with paint pellets. Also, the gold is not real as well.
With nothing left to find, Duke parts ways with the three men.
Mitch returns to Las Vegas, preparing for Barbara to meet him there (having found out that he wasn't in Vegas for a business trip, Mitch has planned a last-minute reconciliation with her). However, Mitch is surprised when Duke shows up in his hotel room.
It is here that Duke reveals a secret: the map that Curly had (and that was used for the tourist trap) had a piece missing from a corner. Duke then provides the missing corner, showing that the treasure was reburied a ways off.
Mitch thinks that Duke is joking with him, until Duke reveals a solid-gold bar...the real thing! "It's got friends," the old man tells Mitch.