A Cube Arrives

After realising that they both lead two lives, one when they are with The Doctor and their everyday life in their London home, Amy and Rory conclude that they should choose one to stick with. But before they decide the TARDIS arrives and they are whisked away on another adventure with The Doctor. After returning home, the couple settle back into their everyday routine once more.

Then one morning they discover millions of small black cubes have suddenly appeared all over the world – but they all seem to be inert and do not pose any obvious danger. The Doctor, already there, attempts to understand them. His experiments though accidentally attract the attention of UNIT and a strike team quickly responds led by Kate Stewart, the daughter of Brigadier Alistair Gordon Lethbridge-Stewart (aka The Brigadier). She quickly identifies The Doctor and explains that they have no idea of where they have come from, what they are made from or their purpose. Also due to the cubes' inactivity people have started taking them home and to work. After several days of waiting The Doctor decides the cubes pose no immediate threat and so puts Brian, Rory's father, in charge of watching them.

Bored with all the waiting The Doctor decides to go off in the TARDIS leaving Amy and Rory to continue with their lives and Brian keeping a video log of the cubes. Nine months pass, before The Doctor returns to take Amy and Rory on a journey through time once again. The trip takes on the usual mishaps; a few days journey turns into seven weeks. They return though exactly at the same point of time that they left. But despite this Brian notices that they are wearing different clothes and asks The Doctor the fates of his previous travelling companions; worrying about Amy and Rory’s possible future if they continue travelling with him. The Doctor admits some have died, but promises that he will not allow this to happen to Amy or Rory.

Brian, Rory and Amy

The next day the cubes suddenly become active – including the one in Amy and Rory’s house. Every one of the cubes exhibit different, random effects - including some that begin scanning the world's information networks. Others though are more dangerous including one that attacks The Doctor. Rory and Brian leave to help the hospital, where Rory works, with the recent injuries while The Doctor and Amy are summoned by UNIT to the Tower of London. There they discover that they have captured some of the cubes to monitor them. Suddenly the cubes become inactive again and the world begins to recover.

Unknown to anyone at the hospital a young girl with a cube has been controlling an orderly with a distorted face to capture some of the patients. Brian then crosses paths with two more orderlies acting strangely. They are in fact non-human entities being used by the small girl to kidnap patients from the hospital. Having been discovered, Brian is kidnapped as well and is taken, by the two orderlies, to a lift that is supposedly out of order, where they disappear. Rory, seeing the orderlies enter the out of order lift, follows and finds that the back of the lift is a portal to a spaceship in Earth's orbit.

The Doctor Investigates a Cubed

Outside the Tower of London, The Doctor and Amy debate the merit of travelling the way they do; Amy considers it ‘running away’ while The Doctor considers it ‘running to’. During their conversation, The Doctor realises that the cubes acted out to gain attention and have also scanned the entire planet.

Suddenly the power at UNIT goes out, and the cubes begin a slow countdown from seven. At zero they all open but The Doctor, who has placed himself in a containment room with one of the cubes, discovers that it contains nothing. Moments pass before reports flood in, from all around the world, of people dying from cardiac arrest. The Doctor then experiences heart failure when one of his two hearts stops. He realises that on opening, the cubes sent out an electrical impulse that has killed about one-third of the human population.

With The Doctor’s help UNIT manages to trace a communication from the cubes to seven different outposts across the world, including one at the hospital where Rory works. The Doctor and Amy leave for the hospital where they discover the little girl with the active cube – The Doctor revealing her to be a simple android overseeing the entire operation. The Doctor shuts her down and Amy restarts The Doctor's heart with a defibrillator. The Doctor then discovers the lift and the portal to the spaceship that Rory had discovered earlier.

Kate Stewart

The Doctor and Amy arrive aboard the spaceship through a wormhole and discover the two orderlies - The Doctor quickly disabling them. They are then met by Rory before they discover Brian. While Amy and Rory take Brian back to the hospital The Doctor meets the spaceship’s on-board hologram.

The Doctor discovers that the spaceship was built by The Shakri, who, according to The Doctor, were a Gallifreyian legend of ‘pest controllers’ in the universe. He also learns from the hologram that the stolen electricity was used to exterminate the human race - which The Shakri considers is a contagion to be destroyed before they spread across the galaxy. The Shakri then prepares to launch a second wave of cubes to kill even more humans before disappearing.

Returning to the spaceship, Amy and Rory watch The Doctor use the spaceship's computer to reverse the shock the cubes gave to the original victims - so restoring them back to life. The surge however, destroys The Shakri’s spaceship just after The Doctor, Amy and Rory escape back to Earth.

As the world recovers, The Doctor prepares to leave when Brian insists that Amy and Rory should continue to travel with The Doctor - stating that the adventures they have with him are a once-in-a-lifetime event and that they should enjoy this unique opportunity.