The Doctor did originally offer Martha one trip in the TARDIS - but extends this to one trip into the past and now one trip into the future. He takes to the TARDIS to New New York in the year 5,000,000,053. But instead of materialising above ground the TARDIS materialises in the inner/underground area of the city - where the real action happens.
Oddly there aren't many people. Sensing new customers three people immediately offer the Doctor and Marta drugs offering emotions. A woman appears to buy forgetfulness from one of the dealers; she is trying to forget about her parents who have gone to the motorway. A few moments later two people appear and kidnap Martha, taking her to the motorway.
The Doctor follows and sees multiple lanes, both up and down and across, of gridlocked vehicles, and no sign of the people that took Martha. There is a fast lane. In order to gain permission to use the fast lane a vehicle must have three occupants, which is why Martha was kidnapped.
As the motorway is under ground the fumes begin to choke the Doctor. A stationary, due to the gridlock, vehicle opens and the driver, Brannigan, offers the Doctor sanctuary. Inside Brannigan tells the Doctor about his journey on the motorway. During the time on the motorway he and his wife have given birth to a litter of kittens. They have several years left to go before they get to the freeway.
The Doctor uses the car's communication system to try to track down the car that has Martha. He tries to get through to the police - but they are engaged!
The bottom lane of the motorway is the fast lane, where the car taking Martha and her kidnappers is managing good speed - 30 mph. But there is something else down in the fast lane, and another vehicle tries to warn them. When the other vehicle is destroyed Martha surmises that the creatures - living in the dark, respond to noise, and suggests stopping and turning off the engines.
The Doctor is able to locate Martha, and sets off to get to her by opening a hatch in the bottom of the car and jumping to the car below, and opening a hatch on the top. Every car is the same which make it a little easier.
Unfortunately, as the Doctor gets to Martha, one of the nurse cats from when the Doctor was last on New Earth - Novice Hame - bursts in and transports the Doctor.
Since the Doctor's last visit things have gone very wrong. A disease has killed everyone in the Senate of New New York. Only Novice Hame and the Face of Boe survived. With the Face of Boe's help Hame managed to seal the underground city, condemning the people to a never ending gridlock, but they are alive.
There is no sign of the virus; the Doctor knows how to free the people, but there is not enough power in the system to open the doors. The Face of Boe, who is dying, releases energy that allows the system to power up and the doors to open, allowing all the trapped cars to escape. The Doctors asks the car that has Martha to come and meet him.
Martha is in time to see the Doctor standing by the dying Face of Boe, who's tank has broken. For once the Face of Boe can feel fresh air. Before he dies he tells the Doctor 'You Are Not Alone'.
- Martha Jones: Freema Agyeman
- Brannigan: Ardal O'Hanlon
- Novice Hame: Anna Hope
- Milo: Travis Oliver
- Cheen: Lenora Crichlow
- Valerie: Jennifer Hennessy
- Alice: Bridget Turner
- May: Georgeine Anderson
- Whitey: Simon Pearsall
- Javit: Daisy Lewis
- Businessman: Nicholas Bolton
- Sally Calypso: Erika Macleod
- Ma: Judy Norman
- Pa: Graham Padden
- Pale Woman: Lucy Davenport
- Pharmacist 1: Tom Edden
- Pharmacist 2: Natasha Williams
- Pharmacist 3: Gayle Telfer
- The Face Of Boe: Struan Rodger
- Teenage Cyber Punks: Naomi Hayama, Kaman Chan
- Naked Lad: Chris Ilston
- Naked Girl: Grainne Jougin
- Red Man: Andrew Cameron
- Vestal Virgins: Holly Dymock, Hayley Jones
- Crowd: Nina Kitt, Paul Ganney, Stephen Bracken-Keogh, Daryl Adcock, Lauren Bracewell, Wendi Sheard, Jenny Pink, Nicholas Wilkes
|BBC 1||3. Gridlock||Saturday, April 14, 2007 7:40 PM - 8:25 PM||8.4M||86|
Repeat Broadcasts on the BBC
|BBC 3||Gridlock||Sunday, April 15, 2007 8:00 PM - 8:45 PM||0.8M||86|
|BBC 3||Gridlock||Friday, April 20, 2007 9:00 PM - 9:45 PM||0.3M|
|BBC 3||Gridlock||Monday, July 16, 2007 7:00 PM - 7:45 PM|
|BBC 3||Gridlock||Tuesday, September 4, 2007 7:00 PM - 7:45 PM|
|BBC 3||Gridlock||Tuesday, December 11, 2007 7:00 PM - 7:45 PM|
|BBC 3||Gridlock||Sunday, January 6, 2008 7:00 PM - 7:45 PM|
|BBC 3||Gridlock||Wednesday, November 19, 2008 7:00 PM - 7:45 PM|
|BBC 3||Gridlock||Thursday, February 26, 2009 7:00 PM - 7:45 PM|
|BBC 3||Gridlock||Monday, May 11, 2009 7:00 PM - 7:45 PM|
|BBC 3||Gridlock||Wednesday, September 16, 2009 7:00 PM - 7:45 PM|
|BBC 3||Gridlock||Thursday, November 5, 2009 7:00 PM - 7:45 PM|
|BBC 3||Gridlock||Thursday, February 11, 2010 7:00 PM - 7:45 PM|
|BBC 3||Gridlock||Friday, October 15, 2010 7:45 PM - 8:30 PM|
|BBC 3||Gridlock||Saturday, February 25, 2012 7:00 PM - 7:45 PM|
- Upper Boat Studios, Trefforest
- The Maltings, East Tyndall Street, Cardiff Bay
- Unit 7, Ely Papermill, Sanatorium Road, Cardiff
- Welsh Centre for Internation Affairs, Temple of Peace, College Road, Cardiff