Traces the fascinating history of the human/dog relationship. Dogs were the first animal ever domesticated and this long-shared alliance has intertwined their biology with ours. This episode explores the evolution of dogs' most powerful 'weapon' against us - puppy-dog-eyes, as well as studies that prove dogs can read our facial expressions and their uncanny ability to understand our emotions. Scientists reveal dogs are so uniquely skilled at understanding our gestures, that they even outperform non-human primates such as chimps.