David and his uncle, a warden of Kenya's National Park, drive to the airstrip to meet David's cousin Susan. The park's only rhino, Black Beauty, wanders onto the runway, causing Susan's plane to abort landing. The rhino crazily charges the jeep. Seeing a wound on Beauty's shoulder, the warden thinks it best to put her down, but David pushes his uncle's gun aside and she escapes.

Susan is impractically dressed in frills, and unhappy at the dusty conditions and mosquitoes. Uncle quietly explains to David that her mother is in hospital for an operation and Susan doesn't know how serious it is, so they must keep the girl's mind off it.

Trusted tracker Shabani finds a spearhead near the airstrip, recognised as a particular tribe's. Next day the warden, David and Susan - now suitably dressed in jeans - visit their village. The colonial District Commissioner is already there, investigating claims that Beauty attacked last night. When David notices a damaged hut has been destroyed with man-made tools, Uncle smells a frame-up. With tribal conflict banned, the tribesmen will do anything to justify hunting the park's wildlife to prove their manhood. The DC offers to ban the hunt for 24 hours, but it's clear Beauty is running out of time.

The warden sets out to capture Beauty, but returns with the jeep damaged and assistant Baaba hurt. The rhino is out of control and, sadly, must be shot.

Next day, the warden bumps into the DC, who claims to have seen Beauty almost 30 miles away at Crocodile Gorge, but suddenly the rhino is there with them. Failing again to shoot her, the warden has the kids returned to the lodge so he can continue tracking the beast. David and Susan 'borrow' a jeep, aiming for the gorge via a secret shortcut, not knowing its brakes need repairing. Following a death defying drive, the jeep overturns, injuring David's ankle. Passing lions and elephants, the children find Beauty in the gorge. David, now watched by both his armed uncle and tribal hunters who have disregarded the DC's orders, tends her wound and removes a dart from her hide. The DC's men arrest the illegal hunters.

Returning to the lodge, Susan learns her mother has recovered from her operation. Then the warden sees Beauty and another rhino - she's found a mate and wasn't the last rhino after all.