Conan, Ran, and Kogoro arrive at a chicken egg factory. Kogoro is asked to investigate what`s causing the strange things that have been happening to chicken sexer Nanba over the past few weeks and act as his bodyguard. They question the factory employees, but nobody can think of anyone who would want to harm him. However, one of his colleagues seems to have reservations about him. Furthermore, they learn about a chicken sexing legend from the reporter who has come to the factory to gather information. Later, when they attend Nanba`s lecture, they witness an attack on him...