Marty adopts a young Tibetan mastiff but does not know how to train it. Like a professional, BT guides Marty along. It turns out that BT grew up with a dog. Inspired by the young Tibetan mastiff, Professor Chin invents Mobile Mastiff, a new device that looks like a robotic dog. During simulation trainings, Mobile Mastiff performs very well, thus solving the Ammobot supply problem. In the meantime, Commander Nick secretly plots to capture Marty again.
