The Hunt for the Seventh by Christine Morton Shaw
Find the Seventh...These are the very words that Jim heard all alone in the garden at Minerva Hall. Can't tell Dad or Sal or anyone, but the fear radiating throughout his body...who could be watching him? What will Jim do?
Since moving to Minerva Hall, strange and unusual things have been occurring randomly, without reason to Jim. in light of his mother's recent death, he cannot bring himself to tell anyone not even family. They had just moved into Minerva Hall, the tower in fact, so Jim's Dad could work as a Gardner for the estate. Everywhere Jim goes he hears whispers...Find the Seventh. The master does not like children, so when summoned to his part of the house, the children are terrified. He tells them that their space is limited to the Tower rooms...too stay with in the boundaries.
That night while looking out the window, Jim sees another boy, sneaking into the maze. he calls out to him but the boy goes on. And so Jim makes a plan to go out the next night to lie in wait in the maze for the boy to return there. So Jim sneaks out of the house, into the maze with a map, so as not to get lost, travels into the maze when suddenly he was there...on a small bench sat the boy. After trying to have a conversation with the boy, who talked in riddles, the boy took off, someone was coming. Jim decides to call the boy Einstein, and before he can leave the bench a girl, a faint image, sort of see through, says "My name is Harriet, I was born in the year 1814." Jim looked away and that's when someone grabbed him.