21st century Dalek invasion

"Ex-ter-minate! Ex-ter-minate! Ex-ter-minate! Ex-ter-minate!"

- Dalek message to Earth

The War in the Medusa Cascade was a war fought between the New Dalek Empire and other races - mostly Humans - in the Medusa Cascade. It was fought in the Medusa Cascade in an environment that held, in a pocket dimension that was one second out of sync with the rest of the Universe, in 2009.

Background
"Welcome to my new empire, Doctor"

- Davros.

During the first year of the Last Great Time War, Davros's command ship flew into the jaws of the Nightmare Child at the Gates of Elysium. Davros, however, was rescued by Dalek Caan. Caan was the last surviving member of the Cult of Skaro, which had been destroyed by the Doctor post-Time War in 1931. After activating an emergency temporal shift for the second time, Caan entered the timelocked Time War and rescued his creator. (DW: The Stolen Earth)

Davros made Caan his prophet, and set to work reviving the Dalek Empire of before the Time War. After building the Crucible, restoring the Dalek Fleet to 200 ships, and creating thousands of Daleks with the Kaled mutants inside grown from the cells of his own body, Davros set to work with creating a Reality Bomb. This superweapon was to destroy all of reality in every universe except for the Crucible, leaving Daleks as the only species in existence. (DW: Journey's End)

To complete this task, 26 planets and one moon were stolen from various times and places across the universe. These included Earth, which brought the problem to the Doctor's attention. The Shadow Proclamation, after the Doctor's visit to them, wanted to go to war with the unknown (to them) perpetrators of this event. However, the Doctor did not wish for a full-scale war, and left to the Medusa Cascade itself.

Invasion
"We have waited long for this ultimate destiny. Now the Daleks are the masters of Earth!"

- The Supreme Dalek

Not long after the planets were brought into the Cascade, the Dalek Fleet attacked. Most of the efforts seemed to go to Earth. The Unified Intelligence Taskforce fought back, but were slaughtered. The Valiant was destroyed nearly immediately by a swarm of Daleks, and military bases across the planet were attacked and all personnel killed, except for Martha Jones, who successfully used Project Indigo to teleport away.


 * It is not clear whether any other planets were attacked by the Daleks. Other worlds out of the 27 were inhabited, and would have presumably put up a resistance.

A subwave network, made by the Mr Copper Foundation and used by Harriet Jones, former Prime Minister, was used in an attempt to help stop the Daleks. While an attack on Harriet's house followed by one on Torchwood 3 stopped the network from fully achieving this purpose, Harriet, Torchwood, Martha and Sarah Jane Smith (with the help of Mr Smith) transmitted a message to the Doctor, helping him to find the location of the stolen Earth. (DW: The Stolen Earth)

However, the Dalek assault continued. Thanks to a time lock in the Torchwood Hub, the Torchwood team survived. Sarah Jane, trying to find the Doctor, was found by Daleks but saved by dimension-hopping Mickey Smith and Jackie Tyler, who then surrendered to the Daleks to find the Doctor, whose TARDIS (with the Doctor, Donna Noble, Jack Harkness and Rose Tyler inside) had been taken to the Crucible. (DW: Journey's End)

Reality Bomb
"THIS is my ultimate victory Doctor. The destruction of reality itself!"

- Davros

The Daleks made a weapon called the Reality bomb to destroy all life in every universe in existence. This weapon was powered by 27 planets, which included Earth. The Daleks had stolen these planets for this terrible purpose. They tested the Reality Bomb on a bunch of prisoners including Sarah Jane Smith, Mickey Smith and Jackie Tyler, but Mickey and Sarah Jane managed to escape to a side chamber and Jackie managed to teleport to it with her Dimension Jump once it recharged. This protected them from being reduced to atoms. This terrible weapon would wipe out all life in every universe. In Pete's World (which the Doctor said is further ahead in time than our world) the stars had went out due to the Reality Bomb destroying them. Meanwhile the Daleks captured and tried to destroy the TARDIS with Donna Noble still inside. They would have succeeded if not for the regenerative energy in the Doctor's severed hand triggering a Meta-Crisis in conjunction with Donna Noble in which a new version of the Tenth Doctor was produced. This new Meta-Crisis Doctor and Donna escaped in the TARDIS (which the Daleks and everyone else thought destroyed) and prepared to turn the Reality Bomb on the Daleks themselves. Sarah Jane, Mickey, Jackie and Captain Jack threatened to detonate a Warp Star which would destroy the Crucible if the Daleks did not back down, and Martha Jones threatened to destroy the Earth with the Osterhagen Key if the same thing wasn't done, but the Daleks teleported them all to the Vault and trapped them there with the Doctor and Rose. The Meta-Crisis Doctor and Donna then arrived in the TARDIS to put their own plan into action but were quickly foiled by Davros, who zapped them with his electricity-shooting prosthetic hand. For a moment all seemed lost, however, the electric shock that Donna had received caused her Time Lord side to activate (She was made part-Time Lord when the Meta-Crisis Doctor was created and she gained the Doctor's intelligence) and she became able to manually disable the Reality Bomb and the Daleks, and release the others.

Destruction of the Crucible
"Never forget Doctor, you did this! I name you forever, YOU are the destroyer of worlds!"

- Davros

With the Reality Bomb disabled, the Doctor's companions got rid of all of the nearby Daleks and Mickey held off Davros with Rose's gun. The two Doctors and Donna started returning all 27 planets to where they belonged, but the Supreme Dalek came to the Vault and attacked, disabling the machinery before Jack managed to kill him. All of the planets but Earth had been returned, but the Doctor made preparations to use the TARDIS to tow it back. The Doctors also realized that Dalek Caan had been manipulating everything to lead to the end of the Daleks as he realized how evil they were and needed to be stopped. The Meta-Crisis Doctor used the control panel to overload all of the Daleks' Dalekanium and blast it back destroying the Daleks and their ships and causing the Crucible to start to blow up. The two Doctors and their companions escaped in the TARDIS, and although the Doctor offered, Davros refused to come with them and presumably died when the Crucible blew along with Dalek Caan and all of the remaining Daleks. With the help of Mr. Smith, K-9 and the Torchwood crew, the Doctor was able to tow the Earth back to where it belonged with Sarah Jane, Mickey, Rose, Martha, Jack and the other Doctor acting as co-pilots on the TARDIS.