"Mickey Mouse in Death Valley" is the second story arc from the Mickey Mouse newspaper comic strip. While it was not the first story in the strip, it is notably the first Mickey Mouse story featuring the writing of Floyd Gottfredson. Initially written by Walt Disney himself, he eventually gave the duty of writing the strip to Floyd, who would continue to produce the strips for the next 45 years.
The story begins when Mickey and Minnie encounter Sylvester Shyster, a lawyer who tells Minnie that her uncle Mortimer has passed on and named her the sole heir in his will. They go to Shyster's office for Minnie to sign the papers that will give her the Mortimer estate, but Shyster locks Mickey out of the place and tells Minnie that the estate is worth nothing, but that she will get a lot of money if she sells the estate to him. Suspicious of Shyster's motives, Mickey manages to get Minnie out of the office and they set off to explore the Mortimer estate, sensing that Shyster wants something that's in there. Shyster sends some henchmen, led by Pegleg Pete, to kill Mickey and capture Minnie and make her sign the papers. While Mickey's in there, he is aided by a mysterious black figure who calls himself "the Fox" and he manages to escape Pete and his goons along with Minnie.
After "the Fox" appears and tells them to go back and find what Shyster's after, they explore the cellar and find a bunch of tasty cheese. While eating the cheese in the cellar, Minnie discovers a map, which reveals that Shyster is after: Uncle Mortimer's gold mine in Death Valley. Shyster and Pete manage to snatch the map from Mickey and speed away in their car to death valley. Mickey and Minnie try to catch them with Clarabelle Cow's bicycle, but they crash the bike and are stranded in the open country with no transportation. After camping for a week, Mickey discovers that Shyster and Pete had blown their car's tire just over the hill. The two then chase the villains on horseback and Mickey steals back the map when they stop at a restaurant. Mickey and Minnie steal the villains' car in hope of getting to Death Valley before them, but after crashing the car at the train tracks, they stowaway on a freight train. However, the brakeman catches the two and throws Mickey off onto the mail hook, where he's promptly picked up by the next train. After encountering Pete and Shyster on the train, he hops aboard the freight train and he and Minnie manage to escape the breakman.
Mickey and MInnie arrive at the town of Poison Wells, the "gateway to Death Valley," and decide to get jobs as a dishwasher and waitress to earn money for mining equipment. Pete and Shyster arrive at the restaurant they're working in a few days later, Mickey and Minnie escape them, buy some equipment and mules, and set off into the valley. Pete and Shyster steal a horse and mule to go after them, after which they are promptly captured by the Sheriff to be hanged. Shyster manages to get the Sheriff on their side by telling them that Mickey is a thief who stole their map, prompting a search party of the Sheriff and his posse to track them down. Both parties hit fork in the trail, where they go on opposite roads. Mickey and Minnie encounter an old prospector Rasmus Rat, who tells them that he can guide them to the Mortimer mine. After a couple of days camping, the Sheriff's posse manage to spot them and ambushes the party. As a last resort, Mickey escapes with the Sheriff's horse and leaves Minnie and Rasmus to be captured.
Mickey and the horse have a wild adventure on water rapids while Minnie is placed in jail without food or water until she reveals where Mickey is. When all hope seems to be lost, "the Fox" finds Minnie in her cells and gives her some food. In the meantime, "wanted" posters of Mickey are placed throughout the town, prompting the rangers to find him for the reward money. Mickey, out lost in the valley after losing the map in the falls, manages to find the Mortimer mine and rides back to Poison Wells to prove his innocence, but bumps into Pete (who had gone off on his own after he spyed on Shyster making a deal with the Sheriff's deputy Hank), and handcuffs Mickey to him. After the two trek the desert, Shyster and Hank find them. Suddenly, "the Fox" swoops down from an airplane and gives the Sheriff bail money for Minnie's release and proceeds to take Minnie with him to find Mickey. All the groups meet up at the Mortimer mine, and "the Fox" reveals his identity as Rasmus Rat, who in turns turns out to be the alive-and-well Uncle Mortimer, who says the mine story was a hoax. Shyster and Pete are arrested and Mickey, Minnie and Uncle Mortimer fly on his plane back home, where he says that he's giving the two lots of money for their troubles.