Daisy Darker

For their Nana's eightieth birthday party, Daisy Darker and her entire estranged family assembles on Nana's tidal island and in her disintegrating, Gothic house. When the tide comes in, the whole family will be trapped together on the island for eight hours, and, when a storm hits at midnight, one of them finds Nana's murdered corpse. Her death is followed one hour later by that of another family member, and Daisy realizes there is a killer among the Darkers.