Vanishing of the 7th Grade

Nobody can explain why Sophia Kershaw's classmates have disappeared... Does it have something to do with the arrival of their strange new 7 th grade teacher? At first, Mz. ("not Miss, not Mrs., not Ms.") Salem is playful and kind, but the woman becomes increasingly sinister as her students begin to vanish on their way home from school. What does Sophia do once she suspects that her teacher is the culprit responsible for all the missing children?