On a peaceful day, urgent knocking at the door jolted Jerry from his sweet dreams. He opened the door to find no one in sight, but at his feet was a basket. Inside was a hungry baby mouse named Nibbles, with a note requesting that he be fed milk. Faced with this helpless little creature, Jerry had no choice but to take on the responsibility of caring for him. Fortunately, there happened to be a bowl of milk in the room; unfortunately, it was placed right in front of the sleeping Tom. Unaware of the danger, Nibbles saw only the milk and not the cat, his reckless actions terrifying Jerry. Though Jerry tried every possible way to get the milk without alerting Tom, their presence was eventually exposed. The stingy Tom, of course, had no intention of giving up the milk to anyone else. He devised all sorts of schemes to deal with the "thieves" disturbing him, and chaos ensued...