On a gloomy autumn evening, Mr. Wajdi, the wealthy and domineering owner of a rare manuscript bookstore, was found dead in his private office at the end of the hall. He died from drops of a fast-acting poison slipped into his herbal tea. The crime occurred within a narrow time window between 6:00 and 6:30 PM. There were only three people in the bookstore, and each claims innocence.