Challenger writes back to Malone agreeing to see him. At the house, Mrs Challenger warns Malone about her husband’s temper. The professor speaks scientific gibberish to expose Malone as an impostor. They fight and in the struggle tumble into the street. A policeman asks Malone if he wants to press charges but Malone says it was his fault. The professor invites him back inside.
Challenger and his wife argue over his unreasonable behaviour. He tells Malone he will talk about what happened in South America but only if Malone promises to tell no-one else. He shows him Maple White’s notebook with the drawing of the stegosaurus and other pieces of evidence. Malone says he believes him and Challenger invites him to the Zoological Society.