Having become something of an expert in alien medicine, Harry Sullivan soon cured both Steven and Zoe of their deadly virus, and offered to join them in solving the rest of the Doctor's problems.
"Thank you Harry. I'll need all the help I can get. Harry, do you remember the time we were crawling through the planet Voga with Cyberman bombs strapped to our backs?" said the Doctor.
"Yes," said Harry.
"Do you remember what I said, when you tried to unstrap mine?" asked the Doctor.
"'Harry Sullivan is an imbecile'," said Harry.
"Well I think I might have been mistaken," said the Doctor, "Of course everyone's an imbecile compared to me. I really should make allowances. Don't you think I should make allowances?"
"If you say so, Doctor," said Harry.
"To the TARDIS, then," said the Doctor.
"Shall we start with Ian and Barbara?" said Steven, "I met them just before they left the Doctor, although we'll be dealing with their earlier selves by at least a few months. They were the first two to be replaced."
"No. I'll need the help of my third self to coordinate a two TARDIS effort to return the dopplegangers to the parallel earth just as the other one of us brings my real companions back," said the Doctor, "Or at least it will be two time period's versions of the same TARDIS. We should swap the Liz Shaws back first. The parallel Liz is, from her perspective, soon to have her first real time encounter with my third self."
The fourth Doctor's TARDIS materialized in the Doctor's laboratory in UNIT, where the third Doctor was silently celebrating the fact that he no longer needed to try to override the Timelords' restrictions on his dematerialization circuit. They all stepped out.
"Zoe, Steven, and two other men," said the Doctor, "Oh, it's you!"
Timelords could always recognize their past and future selves. It was an inate gift that ironically was never meant to be used, as many Timelords believed that it was not wise for them to meet their other selves.
"Is that all you can say?" asked the fourth Doctor, "I did come here to save you from the Master's plot."
"And in so doing, save yourself by defaulting result," said the third Doctor, "I can't say much for your fashion sense."
"Well yours would stand out like a sore thumb, and you have to admit I didn't like your nose, even when it was MY nose," said the fourth Doctor."
"I doubt I'd like your barber, but it's a good thing that Jo and UNIT aren't here to see this."
"Doctor, the Brigadier was wondering if you needed any extra equipment. He sent me to check on you," said Mike Yates entering the room.
This was the Mike Yates who was still UNIT Captain, who hadn't yet betrayed the Doctor in his fanatical ecological obsessions of the last year of the third Doctor's time with UNIT. He would be discharged from UNIT before the Doctor's return trip to the Planet of the Spiders, and would hence never witness the third Doctor's regeneration into the fourth. So it would not confuse the timeline for him to meet the fourth Doctor now.
"As a matter of fact I do need you, but not for equipment," said the third Doctor, "Listen Mike, the fewer people we tell about this the better, but your military skills may come in handy. Would you like to take a trip in the TARDIS?"
"You've got it working, Doctor?" asked Mike.
"Yes, they forgave me and sent a new dematerialization circuit, and this…," said the third Doctor, pointing to the fourth, "is my fourth self. You've recently met my first and second selves when Omega kidnapped a lot of us. Number Four will take us into my personal past to rescue some friends of mine."
"Alright, count me in," said Mike, "I'll just square it with the Brigadier."
"No need for that, Captain Yates," said the fourth Doctor, "I'll have you back here a few seconds from now, no matter how long we take in time and space."
The third and fourth Doctors, and their unique anachronism of a team of companions boarded the TARDISes and took off. Mike went with the third doctor, while the others went with the fourth. The Fourth Doctor's own memory had already partially realigned enough to track the points where the false companions had been inserted into history, based on the details provided by Steven and Zoe from the Master's confessions. He didn't need a time scope of his own. The third Doctor stayed in his TARDIS, to avoid meeting his slightly younger self in 1970. Yates ordered Liz into the fourth Doctor's TARDIS to be taken to the parallel world, while the third Doctor, having retained his knowledge of parallel universe TARDIS travel from the accident (see Infero), collected his own earth's Liz Shaw and brought her back. The Fourth Doctor used a Timelord memory wiping technique to wipe the parallel Liz's memory of recent events, so that she would not corrupt the timeline soon after, when she met the 1970 third doctor for the first time.
Working in reverse order, they then restored Zoe to her correct time and place, while Leela used her fighting skills to subdue the hypnotized parallel Jamie, and then the third and fourth Doctors swapped them back, and explained to the second Doctor what had been going on.
"Oh my giddy aunt!" said the second Doctor, "Do you mean to say that Zoe's absence had something to do with that parallel Jamie?"
"Giddy aunt? Did I really used to say that?" asked the fourth Doctor, "As I recall, she was actually quite steady on her feet."
"It's just an expression," said the third Doctor.
"Then why not use an accurate one?" said the fourth Doctor, "Why not say: 'Oh my steady aunt'!"
"He's impossible," said the third Doctor.
"Meeting you the first time was impossible enough for me," said the second Doctor, walking over to the fourth, "My, oh my, we've really put on height, haven't we? And possibly a little weight too. It's what comes of not getting enough exercise. Haven't you had enough corridors to run down, since you were me, or since you were him?"
He pointed to the third Doctor.
"Maybe I should exercise more. I'll have to go back to playing the flute. Leela's been doing my fighting for me, since I met her and stopped using the Venusian martial arts that Number Three loved so much. Sarah needed so much protecting. You'll meet her in a year, Number Three," said the fourth Doctor.
"I don't want to know," said the third Doctor.
"Well as fascinating and confusing as all this is; don't you think we should be doing something about the other companions the Monk and the Master made off with?" asked Steven Taylor.
"Indeed we should," said the second Doctor, "Do you mind if we start with Victoria? My slightly younger self is still at risk from her double's interference, you know."
Soon three versions of the Doctor's TARDIS were converging on the time and place where they would intercept the parallel Victoria Waterfield. They took her back to her ancient home on the parallel earth's past, and restored the regular Victoria to the second Doctor's slightly younger self, without his more recent self making an appearance in front of his erstwhile counterpart.
Then they did the same for Polly and Ben, making sure the first Doctor didn't see them. Then Dodo, then Vicky, and then they dropped Steven off.
The second to fourth Doctors then collected the parallel Ian and Barbara and swapped them with their counterparts. With all of the companions now back in their respective times and places, the second to fourth Doctors met with the first to debrief the entire affair.