The Lazarus Experiment

After all their travels the Doctor takes Martha back home. Whilst there she receives a phone call to say he sister - Tish - is on TV. She watches the TARDIS leave, and then return as the Doctor notices what was said when Martha turned on TV - that Professor Lazarus was going to change what it mean to be human.

The Doctor accompanies Martha to a launch party Lazarus Laboratories, dressed in a tuxedo, where he meets Martha's sister Tish. Soon after other members of Martha's family arrive, including her mum Francine and brother Leo. Martha feels she has been away for while - even though in linear terms she has only been gone a night.

As things were not going well between the Doctor and Martha's mum Professor Lazarus appears, and steps into his latest invention. When activated the machine starts spinning, and starts to overload. The Doctor manages to stop the overload, but instead of old 76 year old Lazarus that went in, a younger looking Lazarus emerges. After emerging Lazarus starts to suffer from energy deficit, making him famished as he picks up a plate of nibbles. As Lazarus leaves he kisses Martha's hand, leaving a DNA trace that the Doctor can do to perform his own experiments.

Whilst the Doctor and Martha are looking at Lazarus's DNA they see that it is still changing and is unstable. Lazarus and Lady Thaw are upstairs talking about the future when Lazarus starts writhing on the floor. His body mutates into a creature that feeds of the life energy from Lady Thaw.

At the party Martha's mum is discussing the Doctor and Martha with Leo and Tish when Lazarus, in human form, and takes his head of PR, Tish, upstairs to the roof. The Doctor, looking for Lazarus, rushes away from Martha's mum, spilling her drink. When she goes to clean up a man warns her watch our for the Doctor.

On the roof Lazarus and Tish are talking about the experiment when the Doctor and Martha. Whilst Tish and Martha talk Lazarus transforms into a creature. The Doctor, Martha and Tish run back into the laboratory. Alarms sound and the whole building is locked down. The Doctor hands his sonic screwdriver to Martha and tells her to open the doors whilst the Doctor tries to explain to the guests the danger. No-one believes him until a huge spider like creature with Lazarus's face appears.

The Doctor provokes Lazarus to chase him through the laboratory, allowing time for the other guests to get out. Martha helps everyone out then, despite her mum's protests, goes back to help the Doctor.

The Doctor is trapped in a laboratory with Lazarus, and starts opening gas values. As the Doctor leaves he flicks a light switch, igniting the gas and causing an explosion, which unfortunately only annoys Lazarus even more.

Outside Martha's family are attending to Leo when the man Martha met earlier tells Francine that the Doctor is dangerous.

To escape the Doctor and Martha hide inside the Lazarus machine where the Doctor explains that the machine has caused otherwise inert genes in the human body to become dominant, almost a throwback to an earlier age. When Lazarus turns on the machine the Doctor makes the machine affect people on the outside whilst protecting those inside, killing Lazarus and returning him to human form.

As Lazarus is taken away by paramedics Martha is reunited with her family. Francine appears and slaps the Doctor in the face and warns him to stay away from Martha. Before an argument erupts there is a crash. The Doctor rushes over to an ambulance, followed by Martha and Tish, and finds the paramedics drained of life.

The Doctor follows Lazarus to Southwark Cathedral where they find Lazarus, in human form, dressed only in a blanket. Lazarus is in the process of mutating whilst trying to stay human. Lazarus needs to feed and, knowing the Doctor's plan to get Lazarus into the bell tower, offers herself as food and leads Lazarus, followed by Tish, to the top of the bell tower. The Doctor sits down at the organ and, using the sonic screwdriver to amplify the sound, When the Doctor plays the sound is too much for Lazarus, and he falls to the ground. Martha and Tish return to find the Doctor standing over the naked human form of Lazarus.

In Martha's room the Doctor offers Martha one more trip, but she turns it down, saying she doesn't want to be just a passenger. The Doctor agrees to her becoming more than just a passenger.

• Tish Jones: Gugu Mbatha-Raw;
• Leo Jones: Reggie Yates;
• Francine Jones: Adjoa Andoh;
• Lazarus: Mark Gatiss;
• Lady Thaw: Thelma Barlow;
• Olive Woman: Lucy O'Connell (credited as Party Guest in Radio Times);
• Mysterious Man: Bertie Carvel;


• UNCREDITED CAST:
• Security: Paul Bird, John Blackwood, Hugh McInally;
• Drivers: Malcolm Kearny, Wayne Humphreys;
• String Quartet (Violin): Jo Buckland, Sue Lord, Rebekah Brown;
• String Quartet (Cello): Victoria Wadey;
• Waiters: Joseph Lippiatt, Adam White;
• Waitresses: Maria Ohrwall, Alice Mundy;
• Photographers: Greg Bennett, Richard Shaw, Roger Francis, Gavin Hesketh, Richard Price, Mark Soffe, Gemma Murcott, Mandy Garrigan;
• Guests: Greg Bowler, Mark Francis, George Nelson, Justin Claridge, Neil Duffan, Damian Edwards, Gareth Edwards, Jason Jones, Ian Hilditch, Simon Hillman, Tat Wa Lay, Grant Lock, Tony Honeker, Neil Partridge, David Pearson, Vai On Ho, Aiden White, Jason Weeds, Hywel Price Evans, Becky Hart, Jo Whittington, Lisa Winstone, Susan Cazenove, Barbara Fadden, Victoria George, Samantha Harding, Sarah Vaughton, Laura Jones, Darpan Kaut, Sally Martin, Sabrina Morris, Natasha Motee, Arabella Hartland Peel, Sousila Pillay, Toni Rice, Sukhi Kaur, Jillian Wildgoose;
• Older Guests: Ben Fido, Mike Smith, Hilary Morris, Murial Smith;
• Lab Assistants: Sarah Wight, Lisa Unique, Charlotte Green;
• Stunt double for Leo Jones: Charles Jarman;
• Horrified Beautiful Guests: Tracie Simpson, Jennie Fava, Steve Smith;
• Hand double for the Doctor: David Bednall;
• Crowd / Additional Dialogue Recording: Nick Wilkes, Vernon Keeble-Watson, Paul Ganney, Emma Feeney, Wendi Sheard, Joanna Campera;