An old school in a nearby town is supposed to be demolished. But nobody will do the work because of the boiler room. Nobody knows what happened in that boiler room, but it's scared every worker away. Liz, Mack, and Cage meet up with a new sheriff to investigate, but this is one assignment the Fearless Three might not pass! As the adventure unfolds, striving readers practice decoding words featuring consonant trigraphs, as well as inflectional verb endings -ed and -ing. Every Spark Decodables book serves older readers who need practice with foundational literacy skills, combining multiple aspects of the Science of Reading to support small group instruction, independent reading, and reading practice at home.