Ran discovers a receipt for a necklace in Kogoro's wallet and discerns that he is going to give it to Eri as a birthday present. Ran decides to enter a raffle draw to win a luxury hotel trip for her parents and succeeds in winning the tickets. Eri reschedules to meet her client at the hotel upon hearing about the supposed necklace. Her client, Akiho Kokuba, enters Eri's room after getting into a fight with her husband, Takehiko Kokuba, and falls asleep. Eri arranges for Takehiko to retrieve his wife and leaves to eat dinner with her family. She returns to her room, disappointed by Kogoro's behavior and the lack of a present and opens a carbonated drink but is soaked by the can; After showering to wash off the drink, she returns and finds Akiho dead in her room.

Professor Agasa and the Detective Boys visit an aquarium designer named Nishida at his house. Once at the house they knock on the door waiting to be let in. Strangely there is no answer and they are let in by one of the neighbors named Kosuke Imura. The Detective Boys then find Nishida dead in his bathtub.