S01E643 — A Critical Moment from the Karuta Cards (2)

Before Masao is escorted out of the room, he shouts "take out the towel" and declares the towel to have a pattern of a horsehair crab from Lake Suwa. Haibara examines Masao's cards which consist of Ru (る), Ko (こ), Ni (に), and Te (て) in that order. Haibara realizes Masao is telling them to take the words towel (タオル, ta o ru), horsehair crab (ケガニ, ke ga ni), and Lake Suwa (諏訪湖, Su wa ko), and to treat the middle characters as a Japanese particle. In doing so, Ru becomes Ta, Ko becomes Su, Ni becomes Ke, and Te remains unchanged. Reading the changed words from Masao's card order reveals the message Ta Su Ke Te (助けて, lit. "Help Me"). The criminals reveal they have been eavesdropping on their conversation through a cellphone and decide to kill the kids as a result. Haibara deduces they are after the tax evasion evidence of a company that was sent to a television producer from the previous resident of the Urafune household.