The first Doctor, Ian and Barbara had left the earth of the year 2150, with the Doctor's granddaughter Susan Forman stranded there by the Doctor. (See Dalek Invasion of Earth final episode). Ageing and unable to pilot the TARDIS with any reliable accuracy, the Doctor had still been unable to return Ian and Barbara to their correct time and place in earth's history, namely the mid 1960s.
However, he did manage to make a pleasant stopover at a Swiss hotel in the 1920s.
"It could be the closest we'll get to our time and place," said Ian quietly to Barbara, while the Doctor wandered off to explore the hillside, "If we get back in that TARDIS, we could end up on any planet, even killed in a war with some new alien beings we encounter."
"But would we be content to live forty years before our time?" asked Barbara, "We'll both be born in a few years' time."
"Sure, in England," said Ian, "If we stayed here, we'd live out the rest of our lives while our younger selves never met us. It shouldn't cause any trouble in modern history."
"Why settle for that?" said a voice.
The two time travelling companions of the Doctor turned around to see the face of the man who had apparently overheard their conversation. He appeared to be middle aged, had a short beard and slightly foreign eyes, perhaps Spanish.
"What do you know about this? Who are you?" asked Ian, wondering how a 1920s Spaniard could possibly have understood the content of his eavesdropping efforts.
"I am a Timelord, like the Doctor, only not nearly so irresponsible. The Doctor fled our home planet Gallifrey with one of its TARDIS machines, and took his own Granddaughter with him on a glorified joyride which led to his first encounter with you. I've been monitoring his failure to return you to your proper time and place, and I have a friend staying here with me, who should be able to get you back to Coal Hill School, London, 1964, in a TARDIS of his own."
The stranger introduced another man, who had been standing nearby. While having their earlier conversation, Ian and Barbara had paid little attention to him. Unlike the first stranger, the other was clean shaven and dressed in the outfit of a religious man from some bygone era.
"In fact," said the second man, "It's my job to get you back to your correct time and place. We can't have the Doctor shifting people out of their own time periods to jaunt around the universe in a London police box now, can we?"
"Oh Ian, this could be our big chance," said Barbara.
"I have a trip of my own to make," said the first stranger, "My friend will lead you to his TARDIS and take you back to 1964, London."
Ian and Barbara went with the second stranger, and entered another TARDIS. On the outside, it looked like a cabinet of some sort, even smaller than the Doctor's police box TARDIS. However, like the Doctor's, it was much larger on the inside than on the outside, and had a similar appearance of walls with Roundals and a console in the center of the control room.
It seemed like they had been travelling a very short time, before the clean shaven gentleman opened the view screen and showed them a breathtaking sight.
"It's the Coal Hill playground!" said Barbara.
"Just after dawn," said the stranger, "You can get reacquainted with your classrooms and tell your headmaster you were on a long sabbatical forced on you by a peculiar old man."
"Thank you. Words escape me," said Ian.
"Don't mention it. If you'll step out, I'll be off," said the stranger.
Ian and Barbara got out of the TARDIS and left.
They waited for other staff to arrive and then asked the headmaster if they could see him in his office, and soon after did so.
"I know it's hard to explain an absence of over a year," said Ian, "But-"
"Absence. What on earth do you mean?" asked the headmaster.
"Well, ever since we disappeared with Susan Forman," said Ian, suddenly wondering how he'd explain her failure to return too.
"Who's Susan Forman?" asked the headmaster.
"One of our teenage girl students from last year," said Barbara, "It's difficult to explain what happened to her."
"We've never had a Susan Forman in this school," said the headmaster, "And as for this absence you mention, I don't know if you're joking or coming down with some illness, but I've really got work to do. Are you going to be up for your regular teaching duties today, or not?"
"You mean you haven't hired replacement teachers for us?" asked Ian.
"Not unless you're resigning now," said the headmaster, "Now get to work, will you. This is getting tiresome."
"Come on Barbara," said Ian, "We'd better do that."
Outside in the corridor, they tried to make sense of the situation.
"If we've been gone for over a year, how can the headmaster and the students not have missed us?" asked Barbara.
"Maybe the other Timelord took us to 1963, only a day after we left," said Ian, as they reached Barbara's classroom, "Although that still doesn't explain why the headmaster doesn't remember Susan."
"What's this book on my desk?" asked Barbara, "I never had a title like this: Mastering Militarism."
She thumbed through it and scanned a few pages with her eyes.
"What is it?" asked Ian, noting the shock on her face.
"It makes no sense. This text book, if that's what it is, is the most warped version of history and politics I've ever seen."