The Detective Boys attend a triple-feature of Gomera during the final day of a theatre before it is destroyed. During the second film, the man is found hanged. The four theater employees become the main suspects.

Ayumi is sick and is at home with a sore throat. Her mom left the house to go somewhere and a daring thief breaks into Ayumi's house hoping to find money. Ayumi has to warn Conan and the others through her Detective Boys Communication Badge without making a sound since she might alert the thief and that she has a sore throat. Will Conan and the Detective Boys save Ayumi in time?