Things did not go according to plan in Sleightholm's first years as a police dog handler. The difficulties of finding and keeping the right dog were so great that he was ready to give up. Then Cass came along. The two of them quickly formed a bond, graduated as stars from the training school and became an outstanding effective working partnership. Cass became part of the Sleightholm family too. Car thieves, armed robbers, drug dealers, murderers, burglars - Cassius learned to find them, contain them, intimidate and attack if he had to. Sometimes it was dangerous for him. Usually it was more dangerous for the criminal. The story of Cassius is by turns thrilling, funny and moving, and always a fascinating insight into the freemasonry of police dog training. A genius among dogs he may have been, but he was still a dog, an animal that could trust, please, stir every emotion, frustrate,infuriate, delight and, in the end, break your heart.