A street kid has dreams of becoming a jockey. He gets his chance when he and his gang discover a poor old man who has a championship race horse. The man agrees to let the boy ride his horse in a race, but first the gang must get enough money to pay for the race's entry fees.
Dr. Herbert Lee, an archaeologist seeking to decipher ancient Mara inscriptions, is aided by his son Terry, Terry's pal Pat Ryan, and Normandie Drake. Jungle pirate and warlord Fang (Dick Curtis) plots to kill The Dragon Lady, Queen of the Temple of Mara, and seize the treasures of her ancestors. Both Fang and The Dragon Lady have sworn death for any foreign intruders.
After living all his childhood in the street, a young boy rapidly notices that crime doesn't pay, leading him to become a policeman. One day, one of his best friends goes to prison for a murder he didn't commit. The policeman tries his best to release the friend by proving his innocence.
The story concentrates on a travelling medicine show maintained by Bobby Clark and his relatives Minerva Urecal, Earle Hodgins and Joyce Bryant. Their progress is impeded when Hodgins is framed on a robbery charge, but Clark uses his fancy lariat to hog-tie the genuine crooks.
El Puma, a Mexican desert guide, escorts an archaeological expedition headed by Professor Lucius Lloyd through the Indian badlands of Mexico. Marian, the professor's niece accompanies the party as only she can translate the Aztec writings in the diary of her father, murdered on a similar expedition six years previous. The professor is murdered by a knife, and the weapon is recognized as the property of El Puma. Magpie, a Federal Investigator, knows that El Puma is really "Lightnin' Bill' Carson, a former federal agent who has been missing since Marian's father was slain. The reluctant Magpie believes that his old pal is guilty. Carson sets out to prove otherwise.
Two young brothers are separated when their wagon train is attacked and their parents killed. One brother Cherokee is raised by Indians and the other, the Kansas Kid, by the outlaw gang leader Buff. Twenty years later they unknowingly meet again when the Kid goes after wagons being guided by Cherokee.
McCrea plays Joe Meadows, whose only ambition as a Kansas farm boy was a life at sea. He moves to New York to try to get a job as a sailor, finds it more difficult than he thought, and meets Helen Brown, who falls for him and uses her feminine wiles to try to prevent him leaving.