The Other Child(2013)

Successful London doctor Leslie Cramer travels to rural Scarborough to visit her grandmother Fiona and attend the engagement party of her childhood friend Gwen. The sleepy provincial town is in high spirits after the cruel murder of a student. Meanwhile, old Fiona seems to be plagued by guilty feelings rooted in her youth. The situation is getting worse. After a fierce dispute over Gwen's engagement party, Fiona is found dead the following day.