Nothing But Ghosts — Beth Kephart

Ever since her mother passed away, Katie's been alone in her too-big house with her genius dad, who restores old paintings for a living. Katie takes a summer job at a garden estate, where, with the help of two brothers and a glamorous librarian, she soon becomes embroiled in decoding a mystery. There are secrets and shadows at the heart of Nothing but Ghosts: symbols hidden in a time-darkened painting, and surprises behind a locked bedroom door. But most of all, this is a love story--the story of a girl who learns about love while also learning to live with her own ghosts.