"Under Lock and Key" centers around a mystery involving a secret or hidden element, suggested by the title. The narrative likely revolves around a crime or a puzzle that needs solving, with the "lock and key" symbolizing secrets, hidden motives, or concealed elements crucial to the plot.In the first volume, readers are introduced to the central mystery and the key characters involved. The story likely begins with an enigmatic event or crime that sets the stage for the unfolding drama. As the characters are drawn into the mystery, they face various challenges and clues that guide them toward uncovering the truth.