Planet located in the Veruna system. After Earth's sun suffered a cosmic collision, a group of survivors, led by Captain Revere, relocated there. The planet was secretly infected by the Tractators who had drawn the colonists to Frontios because they needed to use their bodies and minds to power their excavating machines. Their leader, the Gravis, planned to turn Frontios into a hollow spaceship with which the Tractators could roam the Universe. The Fifth Doctor defeated him and restored the colony in the hands of Capt. Revere's son, Plantagenet (6N).