Fire and Brimstone

The Eighth Doctor and Izzy materialise on Icarus Falling, a small satellite orbiting Crivello's sun, and witness an attack on it by Daleks. While attempting to stop the Daleks' plans, it is revealed that another of the Doctor's deadliest enemies, the megacorp known as the Threshold, was hired to destroy the Daleks, and already had a plan in motion.