Back to the First Doctor for this one and also the very first introduction of a new companion.
"The Rescue" in many ways almost didn't come about. When Carole Ann Ford, who played the Doctor's granddaughter, Susan, announced that she would not be renewing her contract producer Verity Lambert put plans in motion to replace her with the character of Jenny -- one of the freedom fighters the TARDIS crew would meet during the adventure "The Dalek Invasion of Earth".
Unfortunately issues arose with Hartnell, Russell, and Hill's contracts as well and new questions arose out of the BBC head office as to whether Doctor Who should be renewed after all. With these questions looming, Lambert held off on signing the actress who played Jenny to a contract. Once all the other cast contracts were settled and the show was assured another season it was time to start script writing for the upcoming season. Two previously filmed stories -- "Planet of the Giants" and "The Dalek Invasion of Earth" had been shot at the end of season one but held back to open season two. Lambert decided to use the third story of the season to introduce a new companion.
To echo Susan, Lambert decided to go with another character who was a teenager -- which was a bit of a switch since Jenny had been a little bit older. The two-part "The Rescue" was scripted to introduce the new character. While two-parters were not unheard of for the series they were fairly rare even in the early days and they would go on to become even more rare. The last two-parter of the 'classic' era was the Fifth Doctor story "Black Orchid."
Maureen O'Brien, a young actress, tried out for the role of Vicki mostly on a whim but landed the part. O'Brien was then about 22 years-old playing the teenage Vicki. She would stay on the show for a year or so but then leave, like many actresses before her she became dissatisfied with the part as well as with the fame it generated.
In the meantime, shall we go and meet Vicki?
The Plot: The TARDIS lands on the planet Dido sometime in the late 23rd century. The Doctor, Ian and Barbara are soon confronted by a horrible being named Koquillion and learn that he is also terrorizing the only two survivors of a space ship crash years ago. Teenage Vicki has been spending most of her time taking care of the infirm Bennett but with a rescue ship on its way Vicki fears that the arrival of these strangers will enrage Koquillion and end her hopes of getting off this planet. The Doctor, however, is suspicious. He's been to Dido before and there is something about Vicki and Bennett's story that is not adding up. The deeper he probes for the truth the closer he comes to death!
My Take: Eeeehhhh. The story is alright. At only two episodes it is a fairly tight thing by necessity. There isn't a lot of the usual padding, which is good, but on the flip side some things seem to take place off camera and the audience has to play catch-up between the breaks. There also just plain and simple doesn't feel like there's quite enough meat here; just as one starts to really warm up to the mystery it's solved!
There are several nice bits here though. There is a moment where the Doctor forgets, just for a split second, that Susan is gone, and it brings the grief back to him fresh. Hartnell does a lovely take on this, letting the Doctor seem adrift just for a moment. Later, there is a nice acknowledgement from Ian that he knows why the Doctor has asked Vicki to come along with them.
In the meantime, though, it must be said that the entire cast seem to be having a ball here. Hartnell's Doctor is chipper, humorous, and even a man of action (something he really rarely did) -- seeming to relish this little adventure. He even seems to take facing 'Koquillion' as a kind of lark until it all goes south. Jacqueline Hill and William Russell likewise appear to be enjoying themselves. Their characters are confident and even a bit cocky in attitude and there is some gentle teasing between themselves and Vicki.
Maureen O'Brien seems to be the one who is stuck with some uneven characterization and one 'grade A' hissy fit. In episode one when Barbara proposes setting a trap for Koquillion Vicki is all for it but later she pitches a right temper tantrum refusing to even listen to any of the ideas of the Doctor, Ian or Barbara -- insisting that they are going to ruin everything. I will say, though, that Vicki's reaction to Barbara inadvertently killing her pet is believable for a girl who has been stuck on a planet with almost no other company. The fact that Barbara has killed an innocent creature is disturbing enough but the strain this places on the new relationship is interesting. Unfortunately, like all inter-companion conflict in the early days of the show it is quickly nipped and all is put right.
The villain of the piece is... well... just a villain. Again, the short script and necessity of putting a lot of emphasis on Vicki to introduce her to audiences leaves 'Koquillion' as little more than just a baddie. By the time we learn all of what it going on it is too late and we get no real depth. I will give the writer credit, though, for keeping the mystery a pretty good secret up to the end. Kids watching the program at the time were likely surprised.
In the end it isn't a terrific story but it isn't a bad story either. There are some really enjoyable parts and it is obvious that the cast was having a good time filming this -- the high spirits leak out in the performances. We also get the story aftermath of the first big change in casting and a model is set for companions coming and going -- something that continues to this very day.