Quirky Sleuths. Big Murders. Very Bad Alibis. Lina Mercado notices what other adults dismiss: a shifted chair, a wrong shelf, a missing comfort object, a schedule changed too early. As a special-needs classroom aide, she knows routine is not decoration. It is safety. When district compliance director Graham Vossler is found dead in a sensory therapy room after a furious public meeting, Lina's friend Lila becomes the obvious suspect. The official theory is reasonable. The room is not. A weighted blanket has been folded by someone who wanted the space to look calm — but did not understand what calm actually meant.