The film was shot on location in Rajasthan and Uttar Pradesh, India, with some parts being in present-day Uttarakhand, as well as the Alabama Hills near Lone Pine, California, due to its resemblance to the Khyber Pass.

Meanwhile, Kim encounters an elderly Buddhist lama from Tibet, who is on a quest to find the "River of the Arrow", whose waters will cleanse him spiritually.

Kim notices that their regimental flag depicts a red bull on a green field, which matches a prophecy left him by his now-deceased father, so he sneaks into the encampment.

During the ensuing scuffle, his captors discover documents Kim possesses which show that he is actually the son of Kimball O'Hara, an Irish soldier who had served in the regiment.

The lama decides that Kim should live among his own kind to be educated (despite the boy's resistance) and pays for his tuition at the finest boarding school in India.

Mahbub Ali convinces Colonel Creighton that the boy has the potential to become a wonderful spy; to that end, Kim receives extra training from the shopkeeper Lurgan during the first part of his summer vacation.

While traveling in disguise, Kim overhears a plot to assassinate Mahbub Ali and warns him, saving his life.

Mahbub Ali tosses the emissary off the cliff, rescues Kim and takes the interlopers at gunpoint.

MGM originally announced the film in 1938 as a vehicle for Freddie Bartholomew and Robert Taylor but World War II saw this put on hold.

In 1942 it was reactivated to star Mickey Rooney, Conrad Veidt (as Red Lama) and Basil Rathbone, from a script by Leon Gordon and produced by Victor Saville.