When a close relative falls ill, Hannah Larson and her young son, Nicky, join him for the summer at Ashton Hall, a historic manor house outside Cambridge, England. A frustrated academic whose ambitions have been subsumed by the challenges of raising her beloved child, Hannah longs to escape her life in New York City, where her marriage has been upended by a recently discovered and devastating betrayal. Soon after their arrival, ever-curious Nicky finds the skeletal remains of a woman walled into a forgotten part of the manor, and Hannah is pulled into an all-consuming quest for answers, Nicky close by her side.