A deadly thaw

2004: In Bampton, Derbyshire, Lena Fisher is arrested for suffocating her husband, Andrew. Spring 2016: A year after Lena's release from prison, Andrew is found murdered in a disused mortuary. Who was the man Lena killed twelve years ago and why did she lie about his identity? When Lena disappears, her sister, Kat, follows a trail of clues delivered by a teenage boy