Shot as all 1960's Doctor Who episodes were in black & white, this is a four part serial gives each part it's own name. Only the first episode is actually called 'An Unearthly Child'. That particular 23 minute is set in the same time period it was made in. The story involves history teacher Barbara Wright (Jacqueline Smith) and science teacher Ian Chesterton (William Russell) and a high school student named Susan Foreman (Carole Anne Ford). Susan is a bright but unusual student,whose understanding of history,science and even popular music is filled with unusual gaps,unknown knowledge of events and the general feeling of an observer rather than a participant.
Curious as to this students mysterious identity and her odd understanding of the world around her,Ian and Barbara's concern leads them to a junk yard where they find a blue Police call box and are greeted by a cantankerous elderly man who addresses himself as Susan's grandfather. The teachers force there way into the box to find an enormous space ship on the inside. Despite their expected questions, this mystery man who calls himself "the doctor" (it's Ian's query later of "Doctor?Doctor Who?" that gives the show it's name) abducts the pair into this device which Susan named the TARDIS (time and relative dimension in space),due to the different dimensions that the inside occupies to the outside, and they arrive on Earth in the year 100,000 BC.
The remainder of the serials involve the doctor,his granddaughter Susan and his "kidnapped" companions Ian and Barbara attempting to barter out of a struggle between two factions of stone age humans debating over who has taken the "secret to making fire". Throughout the serial the doctor is depicted as grumpy,unpredictable and in some ways not particularly trustworthy. He seems to be more intent on doing the right thing than necessarily the responsible thing. He even seems to evade his two abducted companions' basic questions about his identity and place of origin.
Overall the debut episode itself is a typical pilot. It does a decent job explaining the basic premise of the program and even the nature of the TARDIS. And 'An Unearthly Child' itself is a compelling,somewhat surreal mystery story. When the plot switches over to the stone age, it starts to lose pace a bit and drags on somewhat occasionally. Major kudos go to Jacqueline Hill and William Russell for their fine acting performances as Barbara and Ian. Very compelling and believable characters. William Hartnell's doctor was well played though the character itself would become far more well rounded as time went on. While not necessarily the place I'd recommend going for an introduction to the show (PBS produced a decent short documentary in the mid 1980's that does the job even better), this is an important historical episode for the show.