Five power cells were located around Khor-shakal to power the dormant Spear of Adun for the day when it would be needed. In 2506, Hierarch Artanis and phase-smith Karax came to Khor-shakal to activate the cells. The two and their allies destroyed the zerg infestation restricting the cells and evacuated the planet within the Spear of Adun.
The power cells are invincible structures that are covered by zerg constriction. Destroying the zerg constriction activates the cells. All five must be freed to win the mission.