In five to six sentences, summarize the events in "Dr. Lanyon's Narrative." Think about the chapter's important details and events.

Dr. Lanyon writes in his letter that he received a letter from Jekyll after the latter's last dinner party. It iseems to be written out of desperation and with no explanation. It orders him to get a specific drawer with its contents from the laboratory, and bring it home. He must wait for a man (Mr. Hyde) who would come to take it precisely at midnight. He learned that Mr. Hyde and Jekyll are the same person. The two personas can morph into one another using a mysterious potion.