The Killing Cross — Louis Tridico

Historian and restoration architect Emma Eaton is busy bringing to life the dilapidated Gladewood Plantation when the owner sends her on an impossible quest: find a legendary and priceless gold-and-jeweled cross rumored to be hidden somewhere on the plantation grounds. There's one catch. A ruthless and relentless rival has stumbled upon an important clue from the past and already has a head start. But as Emma picks up the trail, she awakens a darker, more sinister foe that may be hiding the cross and a secret so devastating, it's worth killing Emma and her friends to protect it.