She was sent on a mission by the War Council of Gallifrey during the Last Great Time War to the planet Ysalus as part of a plot to destroy all life on the planet to change history during a critical war in that planet's history. Aladra had set up a number of bombs in orbit to destroy the Neo Solitarians capital city which would inspire the survivors to devise their own superweapon to retaliate against the Ysalarians which would wipe out all life.
Aladra prepared her TARDIS to send a signal from its console to the orbiting weapons to cause all of this, and she sent Temmis to her TARDIS; as soon as he opened the door, the signal would be sent. (AUDIO: Partisans)