Mother's Day goes wrong and the Maltos discover a toxic threat to Mother Earth.
Many years after the end of the civil war between the Autobots and the Decepticons, the Malto family relocates from Philadelphia to the small town of Witwicky, Pennsylvania. There, young Robby and Mo Malto witness the birth of a new breed of Transformers called Terrans, who become bonded to the two via special cyber-sleeves on their arms. Now adopted into the family and being mentored by Bumblebee, the Terrans work with the children to protect their new life and find their place in the world.