Below Zero begins with an unassuming phone message: 'Tell Sherry April called.' But Sherry - Joe Pickett's oldest daughter, Sheridan - and the Pickett family are shaken to the core. April, Pickett's foster daughter, was killed in a horrific murder and arson spree six years prior. To Joe, it doesn't seem even remotely possible that April could have survived the massacre described in Winterkill. He was there. But Sherry starts to believe there's a chance that April is still alive; the girl on the other end of the phone is able to recall family incidents that only April could know.