Truly Devious Trilogy Book Set in Case Truly Devious Trilogy by Maureen Johnson. The Truly Devious trilogy by Maureen Johnson is a popular young adult murder-mystery series focusing on amateur sleuth Stevie Bell at the elite Ellingham Academy. The series follows her attempt to solve a 1930s cold case while a new mystery unfolds in the present day. The trilogy includes Truly Devious (2018), The Vanishing Stair (2019), and The Hand on the Wall (2020).