The battle for the Movellan ship took place when the Daleks and Movellans arrived on Skaro during their war. The Daleks wanted to find their creator, Davros, to help them win the war; the Movellans wanted to destroy Skaro. The battle took place when Davros was revived and sent his Daleks, strapped with explosives, to destroy the Movellan ship.
Events leading to the battle
When the Fourth Doctor held Davros hostage, he demanded all Dalek prisoners be let go. Approximately forty humanoids were released. The Doctor escaped and Davros planned to evacuate Skaro before the Movellans could attack.
At the time the Movellans were programming their nova device. This bomb would ignite the atmosphere and destroy Skaro. A signal had been sent to a deep space cruiser to come to Skaro. Davros armed approximately forty Daleks with explosives.
The plan was that before the Movellan ship could take off, the Daleks, carrying more than half a megaton of explosives, would press against the hull and Davros would detonate them. (DW: Destiny of the Daleks)
Led by Tyssan and with help from the Doctor, the humans reprogrammed two Movellans and took full control of their ship. They planned to leave Skaro and were unaware of the Dalek force approaching. Davros did not know this and believed it was still manned by Movellans and the Doctor.
The humans armed themselves with Movellan weapons and Tyssan ordered a charge on the Daleks. The Daleks opened fired; the humans' weapons made no impact on them.
Off the battlefield, Davros had the detonator with him, ready to destroy the ship. The Doctor made his way into the Dalek base and confronted Davros, only to be held at gunpoint by another Dalek. He blinded the Dalek by throwing his hat onto its eyestalk. As it fired around the control centre, nearly hitting Davros, the Doctor threw an explosive on its casing and pushed it down a hall, where it went off.
The cruiser never arrived and the nova device was never activated. The humans and the reprogrammed Movellans left Skaro to meet with a high security ship from Earth. Davros, their prisoner, was placed in a cryogenic freezer and was to be put on trial for his crimes against the whole of sentient creation. (DW: Destiny of the Daleks)