Human-Hath War

The Human-Hath War was a war on the planet Messaline that lasted seven days and began when the terraforming colony lost its mission commander. In the power vacuum both factions turned greedy and raged war on each other. They recalibrated progenation chambers originally designed to quickly create workers to breed generation after generation of soldiers, and with due to high casualties went through about 20 generations a day.

By day seven the original mission profile had passed into legend and all the survivors knew was that they had to search for a now-mythical weapon called the Source, in reality the device needed to jump start the terraforming process.

At that point the Doctor arrived, found the Source, and used it to demonstrate to the combatants their true mission and thus end the war. (DW: The Doctor's Daughter)