In August 1992, a mother and her two young sons were brutally hacked to death in the woods behind their home. The boys were just three and one.The neighbour, Andrew Gyle, was convicted and sentenced to life imprisonment.Now, twenty-three years later, a sinkhole emerges in the garden of the murdered family. In the wreckage, a grisly discovery is made. It may even throw Gyle’s conviction into doubt.Andrew Gyle always maintained his innocence. What if he really didn’t do it?Meanwhile, Anderson is back from his leave of absence, but Costello worries he is struggling to cope. His increasingly erratic behaviour makes her think the unthinkable: can she trust her own partner?