狗不但是人類的朋友，更可以成為人類的保衛者。我們熟知的警察警犬隊成立經已有60年歷史，本集將與大家一同追蹤警犬一生：出生、受訓、執行職務、退休。警犬不單是偵緝工具，領犬員本身亦為愛狗之人，對所領警犬也有深厚感情。 Our four-legged friends are not only our companions, they’re also our enforcers of the law and protector of our flora and fauna. Police dogs are the most well-known and developed working dogs among all the disciplinary forces. We look at how police dogs are chosen and trained in their early years, what they do, how they bond with their handlers and what happens when they retire. Besides the government, private security companies are also training canines to protect lives and property.