Conan solves the case and allows the person Sherry suspects to be a black organization member to stay at Shinichi's House. There is a rain of paper planes which people have labelled a prank. Afterwards Conan finds out the planes have morose code with the words S.O.S. Ran with Sonoko tagging along, is on her monthly cleaning trip to Shinichi's house and finds Okiya Sabura. They show the plane to Okiya and he tells them it's an S.O.S.

Mouri is invited by a horoscope reader to meet for the publisher. She is later found dead in her room. Conan figures out the culprit by figuring out his simple plan.