[3] It stars James Franciscus, Kim Hunter, Maurice Evans, and Linda Harrison, and features Charlton Heston in a supporting role.

Time-displaced astronaut Taylor and the mute Nova[a] travel through the desert of the Forbidden Zone in search of a new life away from Ape City.

The gorilla General Ursus leads a rally for the apes to conquer the Forbidden Zone and use it as a potential food source, against the objections of the orangutan Dr. Zaius.

Following a humming sound deeper into the tunnels, Brent becomes agitated and erratic and attempts to kill Nova, before stopping and backing away to another room.

During the ritual, the telepaths remove their human masks to reveal disfigurements of sickly pale skin, scarring and vascular varicose disease.

One mutant, explaining that they cannot let them leave the city alive for fear of revealing it to the apes, uses his telepathic powers to force Brent and Taylor to fight each other.

After Nova is killed by a gorilla in the midst of the chaos, Taylor and Brent reach the cathedral as Mendez, the telepaths' leader, is shot dead after raising the bomb into activation position.

When Brent is gunned down after killing Ursus, the mortally wounded Taylor curses Zaius, collapses and dies bringing his hand down on the bomb's detonation switch.

[citation needed] Then the producers turned to the author of the original novel, Pierre Boulle, who wrote a draft for a sequel called Planet of the Men, where protagonist George Taylor would lead an uprising of the enslaved men to take back control from the apes as the gorilla general Ursus wants to fight humans.

Associate producer Mort Abrahams then wrote story elements, and British writer Paul Dehn was hired to develop them into a script, tentatively called Planet of the Apes Revisited.

One of the elements thought up by Abrahams and Dehn was a half-human, half-ape child, but despite even going through make-up tests this was dropped due to the implication of bestiality.

[6] According to screenwriter Dehn the idea for Beneath the Planet of the Apes came about from the end of the first installment which suggested that New York City was buried underground.

[7] Although Charlton Heston showed little interest in reprising his role as Taylor, studio head Richard D. Zanuck thought the actor was essential to the sequel.

Television and film director Ted Post was approached, and while objecting to the script for "not making a point at all", the producers asked what he did not like.

[14] For the LP, Rosenman was asked to rearrange his score for a smaller orchestra, adding contemporary elements such as electric guitar and rock percussion.

The soundtrack featured some of the leading Los Angeles studio musicians of the time, including bassist Carol Kaye and Moog pioneer Paul Beaver.

[15] A short sequence of diegetic music features in the scene set in the ruins of St. Patrick's Cathedral, in which the telepaths are heard singing a dystopian hymn in praise of the atom bomb.

For this scene, Rosenman composed a discordant setting of Cecil Frances Alexander's 1848 Christian hymn "All Things Bright and Beautiful", with the lyrics altered to pay homage to the "Bomb Almighty".

[27] A. H. Weiler of The New York Times wrote that the film was "proof, in living color, that Heston is vulnerable and that a sequel to striking science fiction can be pretty juvenile.

"[29] Gene Siskel of the Chicago Tribune gave the film two stars out of four:Missing from the sequel is much of the droll humor of the original as well as the adventure.

[32]The Monthly Film Bulletin declared: Certainly it's nice to see some of the magnificent settings again, and most of the acting is of a high standard; but this isn't enough to transcend the script's limitations or the virtual annihilation of the original's deftly constructed atmosphere.

The consensus states: "Beneath the Planet of the Apes offers more action than its predecessor -- unfortunately, at the expense of the social subtext that elevates the franchise's best entries.