The Hidden - The Haunted Series, #1

The night my sister died, a man came to me, he wanted to make a deal with me. Little did I know he had another thing planned. Cleo Martin, a 17-year-old girl, finds out about a hidden world of paranormal beings after an ancestral curse was passed down to her after her eldest sister, Natalia, died. To understand the new world around her and her curse, Cleo gets set to Cypress Institute, a special school on an island just off the coast of Scotland. She and her other sister, Katie attend the school.
While trying to figure out why the curse skipped Cleo's older sister, Katie. Katie, the brilliant witch that she is, helps Cleo to understand this new world and what really happened on the night their older sister died. All while they are trying to stop Mortimer from breaking the family curse. Follow Cleo's and Katie's journey into a new while trying to stop an ancient evil that has plagued their family for generations.