The Missing Key

Nin is a young detective. One morning, her phone rings. It is Mr. Boon, the hotel manager. "A guest is missing!" he says. Nin drives fast to the Grand Hotel. The guest is Mr. Green, a rich businessman. His door was locked from the inside. Mr. Boon cut the chain and opened Room 6. The room is empty. His bag and coat are still on the bed. But his room key is gone. "At nine o'clock, he is going to sign a big deal," says Mr. Boon. It is eight o'clock now, so Nin has one hour. On the table, she sees two teacups. One cup has red lipstick on it. But Mr. Green has no wife and no friend here.