In San Francisco, Squidge Sullivan, press agent for the Putnam and Bailey Circus, contrives to tie publicity about his lion tamer, Jakra the Magnificent, with news of the rescue of Tama, a young woman claiming to be the long-lost heir to the Chase fortune. Although Tama, who was rescued from the jungles of Malaya by Professor Thornton, is welcomed by the Chase family, they demand proof of her heritage, especially after Jakra rejects Tama's claim that her pet tiger can swim. Tama returns to the jungle with Jakra, his girl friend Carol, Sullivan and Thornton, to look for a metal box containing the papers of Tama's parents, who were killed when an elephant, Mabok, rampaged through their village. Native Malayans agree to escort the expedition to Forbidden Valley, home of Mabok and Tama's former village, and as the group makes its way through the jungle, Jakra falls in love with Tama and sees that her tiger friend, Naya, indeed swims. The natives, who learn that there is no treasure at the end of the journey, attempt to kill the group and steal their supplies, but flee after a protective Naya attacks one of their members. Later, they are killed when Mabok goes on a rampage. Tama leads the group to the island where she grew up alone, safe from Mabok, and they then sail a raft to the site of her former village. They find the boxes containing her parents' papers but must escape to the island when Mabok returns. Jakra and Tama remain to build a trap for Mabok, and as they confess their love for each other, Carol and Thornton, on the island, also fall in love. In the morning they lead a rampaging Mabok on a chase, which ends when the elephant runs through their trap to a cliff and falls to his death.