It's the part where hired goons keep coming out of a trap door and Psmith hits them with a stick, and then the hired goons argue about who will be harmed most by being hit with a stick. Looks like that's Chapter XXI in Psmith, Journalist, if you're feeling morbidly curious. (I was reading this otherwise perfectly ordinary book on a plane and was seized by intense embarrassment when I came to this chapter and realized what I was reading in public.)