S1·E8 Watadamashi-hen: Cotton-Deceiving Chapter, Part 4

Rika has suddenly gone missing and Satoko coldly suspects Keiichi, who was the last one to talk with Rika, but Mion says that she saw Rika speaking with some men in construction uniforms. While looking for Rika, Mion pulls Keiichi away from a locked silo and indirectly informs Keiichi that Rika is trying to kill people and that she needs to put an end to string of murders occurring, which is being led by the Three Great Families.