Dulkis: planet of harmony and enlightenment. Home to the peaceful Dulcians. An oasis of calm in the cosmos - and completely defenseless. The Doctor, Jamie and Zoe arrive to find Dulkis enslaved by the cruel Dominators and their deadly robotic servants, the Quarks. The pacifist Dulcians offer no resistance. Can even the Doctor save a people who are willing collaborators in their own destruction?