City of Ghosts (City of Ghosts #1) : 1

When Cass’s family heads off to Edinburgh, Cass meets a girl who shares her “gift” of entering the world of the spirits. Cass still has a lot to learn about the Veil – and herself. And fast… A thrillingly spooky and action-packed tale of hauntings, history, mystery, and the bond between friends (even if that friend is a ghost…)