Gallant - V. E. Schwab

Sixteen-year-old Olivia Prior is missing three things: a mother, a father, and a voice. Her only companions are the ghouls she sees and her mother's journal, which captured a mind in turmoil. Until she receives a letter from an uncle she's never met, summoning her to his estate - Gallant. But when she arrives, she discovers her uncle is dead and the estate is empty, save for her cousin Matthew and the servants. Gallant is a house of secrets. A house sitting in lonely vigil. A place where the ghouls are powerful. As Olivia searches for answers about her family, her past, she discovers a dark reflection of everything she knew, an ancient realm where ghosts take form, and the dark master sits waiting for her...