Voices in stone - Emily Diamand

Ghosts, clairvoyants, UFO-hunters and the paranormal collide . . .Isis, the daughter of a charlatan psychic, can see ghosts - including that of her dead little sister, Angel. Gray is the son of a UFO-chasing conspiracy theorist. The two became friends over the summer, when they fought a deadly ghost together. So why is Gray now ignoring Isis at school?
On a field-trip to a local mine, the pupils are 'accidentally' coated in dust, which has very odd side-effects . . . Could this be related to the ley lines and standing stones which have been calling to Isis with strange, ghostly voices? The secretive and powerful Organisation know the truth, but can Isis and Gray find out what's really happening, and save a life, with the help of two ghosts?