Books in the The Gateway Trackers series

A malevolent force lurks beneath the streets of Scotland...Jess and Hannah Ballard's determination to protect the Gateways brings them to Edinburgh's Old Town, where a strange phenomenon threatens to disturb the delicate balance between the worlds of the living and the dead. Spirits who wish to cross over are vanishing, and it is up to the Ballard sisters to discover why. The historic Royal Mile holds many secrets, some buried deep beneath the streets of the city itself, and soon, Jess and Hannah find themselves lured underground, facing a threat they could never have imagined. Will they be able to free the forgotten souls, or will the missing spirits be lost in the labyrinth forever?City of the Forgotten is the ninth installment in E.E. Holmes' best-selling paranormal series, The Gateway Trackers.