The Rani and her assistant, Cyrian, are in the console room of her TARDIS, watching the images of the first two Doctors swirling in the air around her before being sucked into a massive Time Tunnel lurking in space near the Rani's TARDIS.

The Fourth Doctor is standing in the middle of a swirling vortex, a microphone in front of him. He warns his other selves of the threat of the Rani - she wants to trap them in a time loop for perpetuity.

In the Rani's TARDIS, the evil renegade has nearly completed her "menagerie", her latest addition being a Cyberman and a Time Lord from Gallifrey. The Rani is now ready to intercept the Doctor's TARDIS. A bright flash of light shoots from the Rani's TARDIS and strikes the Doctor's ship, throwing it violently off course.

In the middle of some sort of garden with a huge sailing ship in the water on one side, there is a wheezing groaning sound as the Doctor's TARDIS materializes. The door opens and the Seventh Doctor walks out, followed by Ace. As the two begin walking away from the TARDIS, the Doctor explains they should be in China, but he soon realises they're at the Cutty Sark in 1973. He's suspicious that he has been taken off course. There is a bright flash.

Ace is standing in the middle of a crowded square, 'Albert Square' according to the sign, next to the Sixth Doctor. She seems puzzled to meet him, but is soon distracted by an interesting brown jacket offered by one of the sidewalk merchants. The salesman says she looks great in it, and they're going to be the rage in 1994. The Sixth Doctor suddenly has a grave expression on his face as he hears the year. And there is another bright flash of light.

The Third Doctor is standing in roughly the same location, next to Melanie Bush. Mel wonders what's happening and the Doctor speculates that someone is rooting through his personal time stream. Reaching a fruit stand, he learns from two women that the year is 2013. There is another bright flash of light.

The two same women, but younger, are talking in a similar market. The year is 1973. The Sixth Doctor is walking down the sidewalk with his arm around Susan Foreman. Susan is distressed that he's not 'her' Doctor and starts calling for Ian and Barbara. The Doctor tells her that someone is trying to separate him from the TARDIS, and knows his affinity for Earth.  He adds that the inrush of time zones is designed to seal them all together! Suddenly, there is yet another bright flash of light.

Sarah Jane Smith was wandering down a sidewalk, lost, when she spots the Third Doctor. She begins to run towards him. Sarah catches up with the Doctor and begins to walk with him. She remarks that she thought he would be involved somewhere along the line. He says it's the work of a genius, an expert in time distortion! A time traveller, maybe, and an ingenious operator. Sarah suggests they must get back to the TARDIS but he answers, "It's at the other side of the river." He senses they're flitting around in some sort of twenty-year time loop: 1973, 1993, 2013... He adds that a time distortion of this nature requires an exact localized focus, and contrary to what Sarah thinks, the street market is not the focus.

The Rani is monitoring the Third Doctor's conversation from her TARDIS and fears he may be getting too near the truth. She tells her assistant to "release the specimens".

The Fifth Doctor begins walking toward the Rani, followed by the others. He says to forget what he said about an ingenious operator being behind these time jumps. The Rani, in the meantime, is walking toward them. As the Rani instructs the group of monsters to go back to her TARDIS, the Doctor is trying to summon up his remaining selves? There is a bright light.

Now the Third Doctor and Liz Shaw are in the park. The Rani spins around and aims her gun at the Doctor. She tells the Doctor's companion to come to her. Liz starts walking toward her, then breaks into a sprint. She struggles with the evil Time Lady to gain control of the gun, but another woman attacks the Rani and Liz gets away.

The Doctor looks on anxiously as Liz flees when his yellow Edwardian roadster, Bessie, drives up to the park, driven by Captain Mike Yates of U.N.I.T. The Doctor runs to Bessie, as Mike shoots the Rani's gun out of her hands. She immediately runs inside of the bar and the Doctor and Mike rush away in Bessie.

Brigadier Lethbridge-Stewart is sitting in a helicopter in the air, looking down at Bessie driving up. The Third Doctor jumps out of Bessie and runs to the helicopter, which has just landed. There is a bright flash of light. The helicopter lands elsewhere, and the Brigadier and the Sixth Doctor get out and start walking away from it. The Doctor says to the Brigadier that he must find his young friends.

The Rani is pacing to and fro in her TARDIS. Her menagerie is complete apart from one Earthling. She asks her assistant to prepare to re-materialize at the center of the Earth-time meridian, Greenwich.

Two men walk into a garage and are concerned to find the door unlocked. They suddenly notice a figure crouching behind one of the cars - it's Romana, in her second incarnation. She's looking for the Doctor, but they say that Doctor Legg is the only doctor around. Romana walks out of the warehouse, and down a sidewalk. Outside of Victoria Bar, Romana pauses for a second to look at the Rani's discarded gun. She is suddenly grabbed and dragged into the bar. An evil woman's laugh fills the air, followed by the sound of a TARDIS dematerialising.

The Third Doctor and Victoria Waterfield are walking on the deck of the Cutty Sark. The girl asks about the Rani, and the Doctor states she is behind all this confusion in time although her control is beginning to break down. They enter the TARDIS, and it dematerialises.

In some sort of courtyard, at the Greenwich Meridian, the TARDIS rematerializes. The Seventh Doctor gets out of his TARDIS in time to see the Rani's TARDIS materialize among the pillars of a nearby walkway, disguised as an obelisk.

Leela walks out of the Rani's TARDIS, looking slightly confused for a moment. She looked around until she spots the Seventh Doctor.  She explains that the Rani has got a menagerie of clones and a computer with genetic codes and brain prints of every living creature in the entire universe. The Doctor is very worried, but Leela remembers she was in the form of Romana when she was cloned. The Doctor realises that means there are two Time-brains in the Rani's computer, and they both rush into the Doctor's TARDIS.

Inside the Rani's TARDIS, Cyrian is reading some information from the console and announces that the computer will achieve full power status in thirty seconds.

Back at the Meridian, the Seventh Doctor, now with Ace and K-9, is installing equipment all over the place, some connected to the Rani's TARDIS. He tries to override the Rani's computer and harness the power of the time tunnel to pull her TARDIS in - and not his. Summoning his previous incarnations, the Doctor flips a switch on one of the pieces of equipment. There is a loud bang and an explosion in the Rani's TARDIS. The voice of the Rani, screaming "No" is heard as an aura surrounds her TARDIS, which promptly disappears. The images of the first two Doctors escape the Time Tunnel, and the Rani's TARDIS is sucked into it.