The battle was never supposed to take place. The plan called for the Sontarans to slowly tag the human population of the nearby colony of Raghi in the Unukalhai system with a polymerase chain via a retro-virus in the colony's water supply. Meanwhile, another Sontaran operation was taking place elsewhere in the star system. A small Sontaran unit had captured the human outpost on Agni, one of the moons of the gas giant Indra. The humans were hypnotised and used as slave labour to conduct repairs on a damaged Tzun Stormblade, particularly on its graviton drive.