The design of secret rooms in mystery novels usually needed to consider the following aspects: 1. Clue setting: Set up some clues in the secret room such as puzzles, clue boxes, item lists, etc. so that the reader can gradually deduce the truth of the secret room through these clues. 2. Spatial layout: The spatial layout of the secret room needs to be reasonable, taking into account the possibility of escape and ensuring the comfort and safety of the readers in the secret room. 3. Difficulty setting: The difficulty of the secret room should be moderate, not too simple nor too complicated. It should make the reader have a certain challenge in the process of exploring the secret room. 4. Character setting: Set up some characters in the secret room. These characters need to have a certain background story, personality characteristics, and motivation so that readers can resonate and understand them more easily. 5. Ending Reversal: There must be a reversal at the end of the Chamber of Secrets to allow the reader to have an unexpected ending to increase the fun and challenge of reading. To design a good secret room in a mystery novel, one needed to consider many aspects and have a certain degree of literary attainments and creativity.