Rosalind Joy (Helen Foster) is an heiress who has inherited a South Seas island known as Pleasure Island. A hidden cache of gold is allegedly buried on the island, which has several haunted structures. Rosalind's uncle, Spring Gilbert (Al Ferguson), wants the gold for himself and declares he will stop at nothing, not even the death of his niece, to get it. Rosalind, meanwhile, is befriended by Jerry Fitzjames (Jack Dougherty), a playwright. Unfortunately, Jerry has only recently escaped from a psychiatric hospital. Although he swears to protect Rosalind, she doubts Jerry's sanity. The two lovers race against Uncle Gilbert (who has set several traps for them) to find the treasure. In the end, Rosalind and Jerry are aided by the "Phantom Rider," a spectral horseman.