The plot involves Taylor, a Charlton Heston look-alike who puts his vest on but doesn't do it with the same panache. Astronaut Taylor crash lands on a planet inhabited by apes and gorillas and bonobos and lemurs. He concludes that the civil rights movement has gotten waaay out of hand and something must be done. He teams with a mute lingerie model and together they explore the underground tunnel of this "strange" planet.
But what's this? It turns out he was on Earth all along!
That's right, he's in the New York City subway system, minus the rats and Donald Trump. You bastards! You blew it up to hell! Etc.
In this underground world Astronaut Taylor comes across a kooky collection of burn victims who chant hymns and cover their hideous burnt faces with rubber masks (but disdain the ape masks everyone else has on, go figure), and they worship a giant dildo that will explode love all over everyone.
Charlton Heston shows up for a final actor-y scene to shout his lines and make damn sure the franchise is dead. Angry black men shoot him dead with rifles. Irony!
As he dies, he pushes the Electro-lite button that sends the love bomb to destroy everything. The voice of God then comes on to tell us that an "insignificant green planet" has been wiped out. And yet not even God, nor utter annihilation, could stop the next sequels. Such is the power of the NRA!