A mystery story has five essential elements, which include the characters, setting, plot, problem and solution. Separately, these are important, but they also must interact in a way that is logical and interesting for the reader.
The characters are the people involved in setting up and unraveling the mystery. There is one or more main character on whom the story centers as well as minor characters who help or hinder the main character. The less essential characters sometimes provide background information or add color.
The setting includes the location and time of the story. Often, the setting is described in detail because it contains valuable clues that the characters need to solve the mystery.
The plot is like a map for the story, and it includes a beginning, middle and end. As the plot progresses, more information about the mystery is revealed. This helps the readers understand what is happening in order to solve the mystery themselves.
The center of a mystery is the problem. This is typically but not always a crime, such as a murder, burglary or kidnapping. The problem is introduced early in the story, and one or more of the characters has the responsibility of dealing with it. During the plot, clues are introduced that provide information about the problem, such as why it happened and who caused it. Sometimes "red herrings," which are false clues, appear and throw both the readers and investigators off track for a while.
Finally, the mystery must have a solution. At least one character puts together all the pieces that are part of the problem. This occurs because all the necessary clues are hidden throughout the plot, available to both the investigators and the readers.