After bringing her three cubs out of the wilderness to meet Joy and George Adamson (Susan Hampshire, Nigel Davenport), Elsa the lioness takes ill and dies. Left to train the young lions, the Adamsons allow them to roam freely. But when the cubs kill domestic animals in the East African compound and then disappear into the wild, the local game warden gives the Adamsons two months to find them and move them into the Serengeti National Park game preserve. While the Adamsons search for them, desperately fighting floods, poachers and hunters, the cubs encounter other difficulties of life in the wilderness. Bruised and battered following a standoff with a wild beast, they are wounded by a 21-foot python and then driven off by savage storks while attempting to scavenge a dead animal. But when the Adamsons succeed in rounding up the young trio for an eventful journey to the national park, they are set free in the hope they will be accepted by a new pride of lions.