The Arkheon Threshold was a chronic schism that existed on the planet Arkheon. The Arkheon Threshold was a small tear in time that led to the world known as the Planet of Ghosts. The time rift created spectral visions. It was a rumour of a future war between humanity and the Daleks. People believed it had been destroyed forty years ago. The planet was destroyed, but the Threshold remained. It was an objective of the Dalek Empire. They sought it on the planet Hurala. The tide of the war was turning against them. They sought to win by altering time itself.