Sam Battles the Machine!

In book 6, a mysterious substitute teacher arrives at Eerie Elementary. Sam, Lucy, and Antonio think he must be up to no good! They follow him and discover he lives in mad scientist Orson Eerie's old house! And he's building a strange machine! Who is this substitute teacher? Is he trying to free Orson -- to somehow bring him back to life for real?! Sam and his friends are about to find out!