Unbreakable. Kami Garcia. 2013.

When Kennedy finds her mother dead, her world unravels. Then she meets gorgeous identical twins Jared and Lukas Lockhart who reveal that her mother was part of the Legion, a secret society responsible for protecting the world - a society whose five members were all murdered on the same night.

Now the Lockhart need Kennedy’s help to track down the evil being responsible. Will they be able to destroy it before it kills again?