7.4. The Power Of Three

Series 7 - 2012/2013

Writer: Chris Chibnall
Produced by: Marcus Wilson
Director: Douglas Mackinnon
Music: Murray Gold


Amy and Rory have two lives. The hectic, dangerous, 'Doctor' life, and real life full of everyday items such as picking up glasses from the opticians and getting washing tablets. Whilst Amy and Rory get to experience the Doctor's life, he never experiences theirs. Except once.

One night black cubes appeared all over the world, and inside people's homes. Rory's dad, Brian, wakes Amy and Rory at 6.30 in the morning to ask if they had noticed them. In a playground the Doctor is examining one of them.

No-one around the world knows what they cubes are, where they came from, or what they want. All the cubes are identical. The Doctor doesn't know what the cubes are, and doesn't like not knowing. The Doctor tells Brian to watch one of the cubes whilst he starts to rig up some testing equipment in Amy and Rory's kitchen whilst Rory is getting ready for work.

Rory is still in his underpants, getting ready, when the house is stormed by armed men. A woman appears and apologises for the mess. Equipment had detected artron energy, and it had to be investigated. The woman introduces her self as Kate Stewart, head of scientific research at UNIT. She recognises the Doctor from his dress sense.

UNIT has been testing cubes from around the world, and still has no idea what they are or what they are for. Thy have tried to open the cubes but everything they try, including driving over one with a tank, fails. All around the world people are looking after cubes, taking them, taking them to work and posting pictures on the Internet. Kate thinks they are a security threat and would like to gather up all the cubes and take them to a storage facility.

The Doctor surmises that the cubes want to be observe, and so sits around for four days watching the cubes, after which time they still have done nothing. The Doctor can't stand doing nothing, and so whilst Amy and Rory watch the cube the Doctor busies himself around the house, painting fences and mowing the lawn.

As time passes Amy and Rory's real life starts to become more real. Amy commits to being a bridesmaid months in the future, and Rory commits to becoming full-time at the hospital.

Each day Brian is still watching a cube as the Doctor answered, recording everything on video in 'Brian's Log'. In the hospital where Rory works he passes by a girl holding a cube. He eyes flash blue as he passes. In one of the cubicles two identical nurses, wearing masks over the faces, check on a male patient. Scared the man pulls down a mask revealing a hole where there should be a mouth. At the same time a near by cube glows blue.

After nine months people are taking the cubes for granted. The UN even classifies the cubes safe. It's Amy and Rory's anniversary. The Doctor arrives with flowers, and as an anniversary present takes Amy and Rory to the recently opened Savoy Hotel, 26th June 1890. The Doctor promises no complications - but then even he didn't realise there would be a Zygon ship under the hotel with the half the staff being imposters.

After seven weeks the Doctor gets Amy and Rory back to the original anniversary party. Brian knows they have been away as they are wearing different clothing. Brian asks the Doctor what happens to people who travel with him.

After 361 days Brian is still watching a cube. He is tired, and as he drops off the cube moves. All around cubes are moving, and some are opening up and briefly scanning their locations. Amy notices a cube in the bedroom glow, and when she reaches out to touch it spikes quickly take a small blood sample.

In the living room the Doctor is playing on the Wii when a cube starts hovering in front of him. After a while a gun appears and starts firing. As the Doctor ducks out of the way he watches as it starts to surf the Internet. As Rory and Brian go to the hospital after hearing reports of other cube attacks the Doctor, via the psychic paper, receives a summons to the Tower of London.

Under the Tower of London is a UNIT base where various people are studying cubes. Each cube does something different - including one locked in a room that plays 'The Birdie Song' on a loop.

Other cubes have been more malevolent, hacking into various government systems around the world. After 47 minutes all the cubes, around the world, shut down. The Doctor realises that the cubes shut down because they got what they wanted. Moments later the power fails. Each of the cubes is has a number - 7. After a short while it ticks down to 6. The cubes have profiled the whole of Earth with 47 minutes, meaning the cubes knows everything. UNIT sends out messages via news, TV and the Internet to tell people the cubes are dangerous.

The hospital where Rory and Brian are is being evacuated. Rory asks Brian to fetch a box of tape for dressings. Brian isn't sure where the supplies cupboard is, and asks two nurses. Rory wonders where Brian is, and see two nurses pushing a hospital bed. He goes after them but they disappear into a broken lift. When the lift opens in is empty, but one of the walls ripples when touched. Rory walks into the wall...

In the UNIT base the Doctor goes into a room where one of the cubes has counted down to two. He stays there until the countdown reaches zero. The countdown finishes and the cube opens - revealing nothing inside. Watching on CCTV from around the world as people start collapsing. A few moments later the Doctor feels one of his hearts stop. The Doctor, in pain, examines the CCTV and realises that the boxes have all drawn power from the nearest people, causing their hearts to fail.

Scans reveal seven wormholes all linked to Earth. The nearest one is the hospital where Rory works. Rory finds himself teleported to a spaceship. Brian is there on a hospital bed. Amy takes the Doctor, who still has only one working heart, to the hospital. Using the sonic screwdriver he finds an Outlier droid - the girl from earlier who had the cube. He shuts the droid down and it collapses.

Amy, using a defibrillator, restarts the Doctor's left heart, and they set off to find the source of the wormhole, and find the goods lift. They find themselves on the spaceship with Rory. As Amy and Rory get Brian off the ship the Doctor notices a Shakri hologram.

The Shakri plan to eradicate humanity before humans can colonise space, and start phase two which would mean more deaths. As the hologram disappears the Doctor uses the equipment to instruct the cubes to restart all the human hearts. The energy feedback destroys the ship.

The Doctor is ready to leave, and it is Brian who persuades Amy and Rory to keep travelling with the Doctor.

Regular Cast

  • Amy Pond: Karen Gillan
  • Rory Williams: Arthur Darvill

Guest Cast

  • Brian Williams: Mark Williams
  • Kate Stewart: Jemma Redgrave
  • Shakri: Stephen Berkoff
  • Ranjit: Selva Rasalingam
  • Laura: Alice O'Connell
  • Arnold Underwood: Peter Cartwright
  • Orderly 1: David Beck
  • Orderly 2: Daniel Beck
  • UNIT Researcher: David Hartley
  • Contempery passers-by: Juliet Rimell, Henry Burt, Mike Wendell, Dean Anderson, Tony Banham, Justin Beaver, Steve Dury, Dale Henry, Kate Powell, Sion Price, Justin Rogers
  • Pensioners: Elizabeth Elliis, Keith Rose
  • Roadsweeper: Jefon Rhys
  • Children: Rhys Edmunds, John William Carter
  • Male newsreader: Matthew Amroliwala (himself)
  • Female newsreader: Sophie Raworth (herself)
  • Brian Cox: Himself
  • UNIT driver: Tony Banham
  • UNIT soldiers: Steve Dury, Sion Price, Dean Anderson, Justin Beaver, Darren Thompson, Justin Rogers, Kate Powell, Chester Durrant, Adam Sykes, Michael Houghton, Leigh Aliss
  • Double for the Doctor: Matthew Humphreys
  • Herself: Emily Maitlis
  • Laura's fiancee: Rebecca Anderson
  • In-laws: Karen Poolman, Stephen Phelps
  • Great Aunt: Margaret Baiton
  • Waitress: Samantha Bromley
  • Bar guests: Gisela Lee, Victoria Thomas, Tara Baker, Tracy Scott, David Ulett, Dean Hennessy, Iain Gibbons, Allan Gill, Syed Tarak Ahmed, Remington Croney, Michael Sargent, Sy Turner, Amanda Stahl, Rae Carpenter, Mavis Anagboso, Steve Wintle, Georgina Burford, Melody Louise Brain
  • Teenage boy toilet on foot (Mr Ryan): Tim Forrister
  • Porters: Daniel Murray, Howell Jones, Eryl Hughes, Jason Lloyd Shepherd, Aled Hughes
  • Nurses: Tilly Harris, Harriet Young, Lisa Smoult
  • Doctors: Tanya Ong, Tim Beech, Samantha Davis
  • Visitors: Rose Shepherd, Lucy Merley
  • Receptionist (Dani): Ingrid Bastable
  • Paramedics: Andrew Cross, Daryl Matthews
  • Scrubs: Frankie Ward, Libby Nagle, Brya Waterford
  • Security: Simon Devay
  • Patients: Ceri Hopkins, Robert Payne, Marium Nundy, Shane Price, Tom Forrister, Ruby Henry, Graham Smith, Emma Del Pina, Glen Row, Gewn Hester
  • Little girl: Ienez Soloman
  • Party guests: Tony Banham, Steve Dury, Sion Price, Dean Anderson, Justin Beaver, Darren Thompson, Justin Rogers, Kate Powell, Rebecca Anderson, Colin Moody Jones, Tim Reid, Elena Allsopp, Bharta Bhua
  • Savoy chef (Auguste): Mike Wendell
  • Victorian market trader: Juliet Rimmell
  • Victorian passers-by: Harry Burt, Mike Wendell
  • Himself: Lord Alan Sugar, Nick Hewer
  • Herself: Karen Brady
  • Craig: Douglas Mackinnon
  • Beefeater: Richard Husband
  • Driver: Dean Burton
  • UNIT workers: Craig Evans, Mark Behard, Simon Carew, Michael Carrier, Karl Chatham, Pina Harrington, Alex Hockey, Howard Howell, Amy Leyshon, Jonathan Mabberley, Azhar Miah, Daniel Price, Toby Rattray, Fazial Sweeney, Megan Talbot, Daniel Tomlinson
  • Lab workers: Mark Chatham, Simon Chatham, Andrew Evason, Chris Foster, Julian Gillard, Tessa Liburd, Funminiya Oblianade, Darren Rix, Julie Shanahan, Duncan Steel
  • Bodies: Richard Highgate, Amanda Mulford, Mark Snowden, Amanda Tyre

Original broadcast on the BBC

Channel Title Date Viewers Rating
BBC 1 (HD) 4. The Power Of Three Saturday, September 22, 2012 7:30 PM - 8:15 PM 7.67M 87

Click here to show repeat broadcasts on the BBC


  • 'The Apprentice' Studio
  • BBC Roath Lock Studios
  • Upper Boat Studios: Studio 3

Outside Locations

  • Belle Vue Park, Penarth
  • Bute Esplanade, Cardiff Bay
  • Caerphilly Castle, Castle Street, Caerphilly
  • Church Road, Penarth
  • King Street, Hammersmith, London
  • Near Morgan Arcade, Cardiff
  • Neath Abbey, Monastery Road, Neath
  • St. Cadoc's Hospital, Lodge Road, Caerleon
  • St. Nicholas, nr Cardiff
  • Villa Napoli Restaurant, Plymouth Road, Penarth