The Hand on the Wall

You must read the first two books, Truly Devious and The Vanishing Stair, before starting this one. Because it serves as the direct conclusion to the overarching mystery established in the first two installments, the plot and character arcs will not make sense without that prior context.

This installment fully wraps up and solves both the historical 1930s Ellingham kidnapping case and the modern-day murders that occurred at the academy. While the author has written subsequent standalone novels featuring the same protagonist, this book completely resolves the main trilogy's central puzzle.

The novel maintains the dual-timeline structure used throughout the series, alternating between Stevie's present-day investigation during the campus evacuation and historical flashbacks from the 1930s that gradually reveal what happened to the Ellingham family.