Battle of Hedgewick's World of Wonders

The Battle of Hedgewick's World of Wonders was a battle between human forces led by the Eleventh Doctor and Clara Oswald and the Cybermen on Hedgewick's World of Wonders. During the battle, the Cybermen's goal was to escape the planet where they had been left a thousand years before to recover from damage inflicted during the Cyber-Wars while the heavily outnumbered humans attempted to foil their plans.

During the battle, the Cybermen held a significant advantage in numbers and also the fact that their Cyber-Planner Mr Clever was trying to take control of the Eleventh Doctor.

The battle eventually ended when the man known to the participants as Porridge was revealed to be Emperor Ludens Nimrod Kendrick Cord Longstaff XLI who had fled to get away from the pressures of being Emperor. Porridge was able to destroy Hedgewick's World and the Cybermen on it with a planet-imploding bomb while transporting the survivors to safety. However, a single Cybermite survived the battle undetected. (TV: Nightmare in Silver)

Origins
During the Cyber-Wars, damaged Cybermen were transported to a planet by a Valkyrie for repairs. Eventually, three million Cybermen would be sealed in tombs on this planet. The war ended when the Tiberian Spiral Galaxy was sacrificed to destroy the Cybermen. The survival of three million Cybermen on this particular planet would go unknown for over a thousand years. Following the destruction of the galaxy to stop the Cybermen, a protocol was developed where if a single Cyberman was spotted, the planet on which it resided would be destroyed to prevent it from escaping.

Around a thousand years after the Cyber-Wars, a man named Hedgewick bought the planet on which the damaged Cybermen resided. Hedgewick went on to build Hedgewick's World of Wonders, "the biggest and best" theme park in the galaxy. However, patrons began to be kidnapped in secret by Cyber forces in order to repair the damaged units hidden in the tombs below the surface. As a result, the theme park was abandoned aside from a punishment platoon stationed there, Webley and a man going by the name Porridge who was in fact the Emperor who had run away to get away from the loneliness of his job.

After discovering that their nanny Clara Oswald was a time traveler, Angie and Artie Maitland blackmailed Clara and the Doctor into taking them on a trip in the Doctor's TARDIS. (TV: The Crimson Horror) Due to Hedgewick's World's nature as the greatest theme park in the galaxy, the Doctor chose it as the location to take the children to. Upon arrival, they were greeted by Webley and the punishment platoon with the Doctor tricking the latter using his psychic paper.

To the Doctor's surprise, they learned the Hedgewick's World had been shut down but Webley took them to his museum where he revealed a collection including three inert Cybermen, one of whom defeated Artie at chess. The Doctor quickly determined that Porridge was secretly operating the Cybermen and Porridge took the children on the Spacey Zoomer Ride. Before they departed the museum, Angie's interest was drawn by a waxwork of the missing Emperor. Unnoticed by all, they were observed by hidden Cybermites amongst the waxworks. (TV: Nightmare in Silver)