The Folly

Morgan always knew her father, Owen, never murdered her mother. She has spent the last six years campaigning for his release from prison. Finally, mid-pandemic, Owen is set free, but the debt-riddled pair can no longer afford (or bear) to live in the family home - a house last decorated by a dead woman's blood.
Salvation and the chance for a new start in life comes in the form of a tall, dark and notorious decorative granite tower on the Cornish coastline known only as 'The Folly'. The structure is empty, prone to break-ins, and the owner needs a caretaker - food and bills included. It's an offer too good to refuse. Morgan and Owen relocate, leaving everything of their former lives behind and hoping that a change of scene and the remote location will be good for them both.
At first, the Folly is indeed idyllic, but soon enough that peace is shattered when a bald-headed stranger arrives. A stranger who acts like Morgan's mother, talks like her mother, and wears her dead mother's clothes.
What does he want? Why won't he leave them alone? Why does he keep mentioning the year 1976?
And what secrets does the Folly tower hold?