Edward Malone, a young reporter for the Daily Gazette, asks his editor for a dangerous assignment to impress the woman he loves, Gladys, who wishes for a great man capable of brave deeds and actions.
His task is to approach the notorious Professor Challenger, who dislikes the popular press intensely and physically assaults intrusive journalists. The subject is to be his recent South American expedition which, surrounded by controversy, guarantees a hostile reaction. As a direct approach would be instantly rebuffed, Malone instead masquerades as an earnest student. On meeting the professor he is startled by his intimidating physique but believes his ruse is succeeding.
Seeing through the masquerade, then confirming Malone's scientific knowledge is non-existent, Challenger erupts in anger and forcibly throws him out.
Malone earns his respect by refusing to press charges with a policeman who saw his violent ejection into the street. Challenger ushers him back inside and, extracting promises of confidentiality, eventually reveals he has discovered living dinosaurs in South America, following up an expedition by a now-deceased previous American explorer named Maple White.
At a tumultuous public meeting in which Challenger experiences further ridicule (most notably from a professional rival, Professor Summerlee), Malone volunteers for an expedition to verify the discoveries.