The Folly by Gemma Amor

An ex-con, wrongly convicted of his wife's murder and subsequently acquitted, and his daughter move into an abandoned decorative folly on the cornish coastline to escape their past, but a stranger bearing secrets-and an important message-soon catches up with them.
Morgan always knew her father, Owen, never murdered her mother, and has spent the last six years campaigning for his release from prison. After a retrial, a fresh jury acquits him, and he is set free into an uncertain world. A pandemic is sweeping across the nation, Morgan is broke, and both of them have the heavy stench of a highly publicized trial. Both need a change of scene, as Morgan can no longer live in the house that was last decorated by her Mother's blood after she fell down the stairs - the accident her father was wrongly accused of orchestrating. Or was he?
Salvation comes in the form of a tall, dark and somewhat notorious decorative granite tower on the Cornish coastline known only as 'The Folly'. The owner is used to rehabilitating ex-cons, and offers them new life, in exchange for taking care of The Folly. It's an offer that is too good to refuse.
At first, the Folly is idyllic, but soon a stranger arrives who seems obsessed with Morgan's dead mother. The stranger acts like her mother, talks like her mother, and wears her dead mother's clothes. It quickly becomes apparent that he has a message, but with each new encounter, Morgan becomes increasingly unsure as to what that message is, and worse, who it is she is dealing with, exactly: a deranged stranger hell-bent on vengeance, or her restless Mother's spirit itself?
As a strained father and daughter become increasingly uncomfortable in the Folly, the stranger continues to haunt and taunt them. Questions pile up: who exactly is this stranger? Why must he speak, act and dress like her deceased mother? Is her father as innocent as she always thought? And, most importantly, what happened the night her mother died?