“The Lion's Trail” charts the history of “The Lion Sleeps Tonight,” which was adapted from a song written in the 1930s by a South African named Solomon Linda, who never received any royalties (he died in 1962), and whose daughters are seen living precariously in Soweto. No copyright laws were broken, but the South Africans, says journalist Rian Malan, “couldn't play the [legal] games the Americans were playing.” The hour includes performances by Ladysmith Black Mambazo and Pete Seeger.