"No! Not the mind probe."This is a rarity for Doctor Who twofold over. First, it's a multi-Doctor adventure, which had only been done once before and has only been done thrice since then in the TV show proper. Second, this was also the 20th anniversary special for Doctor Who, aired during Children in Need night (though US broadcasting was two days before, on the actual anniversary date of November 23). Finally, this was presented as a Who-movie in one massive part rather than a multi-part adventure, though it didn't stop the BBC from turning it into a 4-parter a few years down the road.
— The Castellan is mildly alarmed at his impending mental torture, but the actor just can't handle the lines.
The Fifth Doctor, Tegan and Turlough have a vacation from their last adventure at the Eye of Orion. (Kamelion, who joined last time, is ignored.) Things are mighty peaceful, until the Fifth Doctor is suddenly struck by pain and has to be dragged back inside his TARDIS. The Fifth Doctor makes mention of something taking away his older lives.note As it turns out, a villain is taking the Doctor's previous lives out of time and space. The First Doctor (here played by Richard Hurndall, as William Hartnell passed away 8 years prior) is stolen away as he meanders around a garden. The Second Doctor is whisked away as he and The Brigadier reminisce about old times, just when the Brigadier is retiring. The Third Doctor is kidnapped along with his car Bessie as they drive along the countryside. Sarah Jane Smith is whipped away from her home and robot dog. The Fourth Doctor... well, something unspecified went wrong, and he's stuck somewhere in time with Romana. note Meanwhile, the Fifth Doctor, his companions and his TARDIS are finally dragged off somewhere else...Cut to Gallifrey. The Time Lords are getting worried. Lord President Burosa, previously seen throughout many adventures, calls for a high council meeting. Someone has kidnapped the Doctor out of time and space, and the Fourth Doctor being stuck in time is a problem. There's only one person they can trust to rescue the Doctor...The Master, of course!Borusa promises the Master a new regeneration cycle if he can pull this off. And the Master seems all too happy to help out, because "a cosmos without the Doctor scarcely bears thinking about." He takes a teleport recall device with him to keep in touch with the Time Lords. Hmm...The First Doctor, wandering through an odd set of hallways, runs into his granddaughter Susan — whom we've not seen since 1964! Quickly, they both run into trouble as a Dalek shows up, albeit one looking like it needs some repair. The Doctor and Susan quickly outwit the Dalek, which shoots itself in the face and explodes. It takes out a part of the wall and showing that they have a rather unfortunate problem: outside lies the Tower of Rassilon. The Doctor correctly surmises that not only are they on Gallifrey, but in the evocatively-named Death Zone! As they continue walking on, they notice a familiar blue box off in the distance...Meanwhile, the Second Doctor and the Brigadier run around and away from Cybermen and also find the Tower of Rassilon. This causes the Second Doctor to wonder if they're playing "the Game of Rassilon" while he recites an old nursery rhyme about the tower (the Nursery Rhyme of Rassilon?). The Third and his giant plaid mantle stumble across Sarah Jane, who has just helplessly fallen down what can only be called a gentle, harmless slope. Sarah Jane tries to figure things out for a few seconds before giving up: as she'd already seen the Third Doctor regenerate into the Fourth, she's confused by Three showing up again, but eventually decides to roll with it. (Three, for his part, is already familiar with "All Teeth And Curls".) They quickly run into his "best enemy" the Master, and the Third Doctor assumes that this is all his doing, steals the Master's proof of working for the Time Lords and merrily drives off again, leaving the Master surrounded by a lot of random explosions.Slowly awakening in his TARDIS, the Fifth Doctor finds himself staring into the face of his first incarnation and his granddaughter. Meanwhile, Tegan and Turlough go to get everyone tea... but come back with a feast, and absinthe! Let the partying commence! It's finally decided that the Fifth, Tegan and Susan will try to get to the Tower of Rassilon, while the First stays behind to munch on fruit and, presumably, Turlough drinks the absinthe. note As the Fifth and companions head out, they quickly run into the Master, who does at least get a little trust from the Doctor before Cybermen show up and blow things up. The Master is knocked unconscious. The Fifth Doctor quickly steals his teleportation device and is whisked back to the high council. Tegan and Susan run off back to the TARDIS, leaving the Master for dead... and Susan sprains her ankle in a tribute to longtime Susan-tormenting writer Terry Nation.The Fifth Doctor quickly figures out how badly things are going up at the Capitol, and the Castellan is found to have betrayed them all and his promptly executed. This doesn't sit right with Five, who sneaks around to explore. The First Doctor and Tegan set out to the Tower of Rassilon. The Third Doctor and Sarah Jane are menaced by Cybermen, but are unintentionally saved by a guardian robot that just kills anything that moves. (A "Raston Warrior Robot", which was such an immensely awesome "monster" it's bewildering they only ever used it once.) They quickly climb up a mountain through a series of cuts and climb over a massive ravine to reach the roof entrance for the Tower of Rassilon. The Second Doctor and the Brigadier, however, go through a cave system (the Cave System of Rassilon?) beneath, fight off a random Yeti, and enter the tower via the Basement Entrance of Rassilon. The Third encounters hallucinations of Mike and Liz, and the Second is confronted by Jamie and Zoe, but they quickly realise that it's all a bunch of holograms. Back in the Lobby of Rassilon, Tegan and the First Doctor encounter a hopscotch-shaped booby trap. Fortunately, the Master wanders by just in time to smirk smugly, defeat all the Cybermen, and toss off a cryptic hint to his old Academy buddy. Thank goodness for small favors.Finally, the first three Doctors are together in the Hall of Rassilon and begin to work out exactly what in Rassilon is going on. Sarah Jane, the Brigadier and Tegan are happy to see one another. The Master shows up, revealing that... contrary to the Doctors' collective expectations, he's not the architect of mayhem this time around. But, as long as he's here in the Tomb of Rassilon, he still plans to steal the immortality-granting Ring of Rassilon from off the Corpse of Rassilon that's lying in state over there in the Casket of Rassilon... until the Brigadier punches him in the face, and the Master is out cold for the rest of the story.Off in the High Council of Time Lords, the Fifth Doctor plays the Harp of Rassilon, which trips a hidden door to the Secret Tree Fort of Rassilon, which means he finally finds out who is behind all of this: Lord President Borusa! It's pretty apparent that Borusa has gone mad with power and wants that Ring of Rassilon to rule Gallifrey utterly forever. He then uses the Coronet of Rassilon to brainwash the Fifth into helping him out, and goes off with him to the Tower to confront the other three Doctors...The TARDIS finally shows up at the Tower. This allows Turlough and Susan to finally leave the TARDIS. They spent most of the adventure being menaced by Cybermen, who were trying to set up an incredibly lame bomb outside the TARDIS for some reason. They're immediately frozen in place by Borusa when he shows up with the zombified Fifth Doctor. The other three Doctors do some mental struggling and free the Fifth Doctor from his possessed form. But they're unable to stop Borusa from finishing off the Game of Rassilon and claiming the Ring of Rassilon from Rassilon himself. Rassilon is not even remotely dead, and booms at Borusa to decide if he really wants to be immortal. The First Doctor, having a lightbulb moment, tells Rassilon to go for it.The so-called immortality (of Rassilon) is not as it appears. Borusa is instantly sucked into the Exposed Casket of Rassilon — forever to be a fully-aware chunk of stone, unable to move. Rassilon sends the other three Doctors and their companions off on their merry ways and frees the Fourth Doctor from whatever the Rassilon was wrong with him and Romana. The other Time Lords show up in quick succession after the action is over (typical, really) and proceed to force the Fifth Doctor into becoming the Presidency of Gallifrey again. Since he has no choice, he names Lady Flavia his representative, tells the Time Lords to go wait for him in the Capitol for a bit, orders his companions into the TARDIS, and hastily vworps off with no intention of visiting Gallifrey ever again. After all, he explains with a grin, "that's how it all started."
This is it — one of the best tales of Doctor Who. The cast and crew loved working on it, the fans loved it... what's more to say? Well, aside from the fact that this story actually went through several iterations. One was that there was to be a story called "The Six Doctors", featuring an android version of the First Doctor called "Doctor Wil". Another was a full story featuring Tom Baker alongside the other Doctors... but it had a heavy focus on him (author Terrance Dicks would explain that he felt Tom's Doctor was the most likely to fall to evil, thus having the meat of the story). This was changed into the final version, with most of Tom's role going to then-current Doctor Peter Davison. A few of Tom's lines have snuck into Peter's lines, though.This story has had two DVD releases: the 25th anniversary release (an anniversary of an anniversary?) is the one to get. Not only does it have the original release, it contains two versions of the story and three DVD Commentary tracks... one with Peter Davison and writer Terrance Dicks, one with most of the rest of the actors, and as an Easter Egg, a warm-hearted geekfest with 10th Doctor David Tennant, New Series script editor Helen Raynor and New Series producer Phil Collinson. There are even a handful of documentaries for the era that long outstrip the actual length of the special: one narrated by 6th Doctor Colin Baker and the other narrated by 8th Doctor Paul McGann.