The Angry Intruder - Christy of Cutter Gap, #3

She could just make out the glimmer of a knife, poised high over the open piano. "No!" she cried, and as the knife came down, she grabbed for the intruder's arm with all her might.  Headstrong and independent, Christy is determined to change the lives of the children in Cutter Gap. Apparently, Christy has angered someone enough to cause a string of mysterious pranks. Miss Alice warns Christy to be careful as the pranks become more threatening.  What will Christy do when one of her own students turns against her?