From the pictures I can see that this story is about the Doctor as played by Patrick Troughton (the story still calls him Dr Who though). This is also shown by having Jamie and Victoria as Companions. They aren't in the story much, though they are at least there unlike the last few stories when the Doctor was on his own.
"He tiptoed across the gleaming floor of the Tardis, so as not to disturb his two young friends, Jamie and Victoria. They were sleeping soundly after a rather disturbing adventure on a strange planet in the dark dimensions of Galaxy "G"."
I think this story of "the dark dimensions of Galaxy "G"" must be missing, like so many of the stories from Patrick Troughton's time as the Doctor. That is sad because it sounds intriguing. The Doctor is off for an adventure by himself. He puts on his hat (I would like a hat like that) and goes exploring.
"Despite his countless journeys through Time and Space, Dr Who found everything of absorbing interest. First, he was struck by the spiny blades of the plants that covered the ground."
Ouch, that sounds painful.
"Then his attention was caught by the three moons that hung like lamps in the velvet blackness of the sky.
"Amazing!" murmured Dr Who. Then with a yell he plunged down into a yawning hole that he had failed to notice."
The Doctor falls slowly instead of quickly, and he thinks this is just like a book Victoria told him about.
"Now what was the name? Ah, yes - Alice in Wonderland! And a little girl had just such a fall as this..."
The Doctor is immediately captured by aliens with "ray-guns."
"The officer was almost human in appearance, except for his amber eyes and forehead antennae. But his platoon was scarcely human. They wore helmets, emblazoned with a golden sun and superimposed black cogwheel, and red kilts and black ankle-boots, but for the rest their bodies were covered with a stiff mat of black hair and their faces were slightly like terriers."
They sound fabulous with red kilts and black ankle-boots. It is a shame Jamie is not on this adventure, I think he would have liked meeting these dog-mannys. The Doctor says he comes in peace but the leader thinks he is a baddy who has come to kill Mufl.
They search him for weapons and find his recorder (or "musical pipe") and think it is a weapon. The Doctor explains.
"It is a pipe. You know? Music!"
"Music?" echoed the other blankly. "What is that?"
Dr Who could not restrain a smile. He held out his hand: "Well, the only way I can answer that is to play some.... Give me the pipe, please."
The officer's reply was to snatch the pipe from the soldier and push it into his belt. "No!""
I think it is quite likely that he would have said "No!" even if he did know what music was, lol. They take the Doctor to the sinister-sounding "answer room." They go down a tunnel and the Doctor sees "the un-winking gaze of television monitor cameras" which either means there is lots of security here or else the story is breaking the fourth wall in a rather odd way.
In the "answer room" they put the Doctor into a machine to "examine his brain" and find out if he really has come to kill Mufl. But then Captain J'nk (the "officer") uses the machine to try and hypno-eyes the Doctor!
""I am Captain J'nk... you will listen to me... you will remember what I say... you will obey....""
The Doctor doesn't remember that he has been hypno-eyesed, or maybe he just confuses it with when he watched The Ipcress File. Captain J'nk pretends to be his friend.
""Our tests prove you speak the truth, Dr. Who.... Forgive this reception - but we must be careful of assassins sent by Kanulf to try and kill Mufl...."
The doctor bowed in return. "I gather that Mufl is your ruler?"
"Exactly!" said J'nk. "And Kanulf rules the rebel race of Hiinds destined to live on the arid surface of our planet Vegan.""
If their planet is called Vegan, does that make them all vegans? J'nk takes the Doctor to meet Mufl, but first the Doctor picks up his recorder to take with him. This has been left lying around for him to find, in case the Doctor needs to make use of it later in the story. Which he will.
The Doctor meets Mufl. He is the only manny allowed in, just in case anybody else turned out to be an assassin. Mufl talks to the Doctor and shows him a picture of his Empire.
""That is the Empire," said Mufl. "Every one of eight hundred and forty-three inhabited worlds... a billion and a half intelligent beings... fourteen races... and all faithful to me except Kanulf and the Hiinds."
I thought "a billion and a half" mannys was not very many for 843 planets, until I remembered (alright, Gamma Longcat reminded me) that Mufl probably means "a billion" to be a million million, instead of a thousand million. That would be a lot of mannys. Mufl then tells the Doctor about the past attempts to kill him.
""Once my robots discovered loose strontium-90 in the upholstery of the Audience Throne. Another time a ray-gun was hidden in the view screen in my bed-chamber. And again a fission bomb was flung at a space-car in which I was thought to be travelling..."
The Doctor begins to remember being hypno-eyesed, and he plays his recorder to help his concentration.
""I've got it!... Now I remember what happened!... Your Captain J'nk sent the attendants and the soldiers out of the answer room.... Then he must have put me under deep hypnosis and instructed me to - to kill you when we were alone in here!"
Mufl doesn't react to this revelation from the Doctor, which itself comes as a surprise to the Doctor until he realises why.
""Great galaxies! He's in a sort of trance.... But how - what - ?"
He broke off, staring at his music-pipe. "Mm... yes! That must be it! From what J'nk said, music is un-known to these people. And it proves to have a hypnotic effect on them!""
The Doctor takes out the ray-gun that J'nk gave him to kill Mufl and then J'nk comes in. He thinks the Doctor has killed Mufl and he has time to gloat - and so give himself away as the baddy - before the Doctor hypno-musics him with his recorder too.
Mufl comes round first and, now he knows J'nk is the baddy instead of Kanulf (who doesn't appear in the story), he is grateful to the Doctor. But the Doctor, as usual, doesn't want to be "guest of honour" at a "great celebration," he just wants to go back to the Tardis.
This is a short story - it is only six pages long, and almost two of those are taken up with the first picture. It still manages to be entertaining and proves that long stories are not always the best stories (though long cats are always the best cats).