In 1963, a mysterious time traveler called "the Doctor" (William Hartnell), his granddaughter Susan (Carole Ann Ford) and two of her teachers, Ian (William Russell) and Barbara (Jacqueline Hill) were inadvertently transported to an alien world, thanks to the Doctor's time machine (the TARDIS) malfunctioning. There, they find a petrified forest and an empty city, where they discover that they've been exposed to dangerous amounts of radiation. But before they can return to the TARDIS to escape, they are captured by the city's inhabitants - robots with domed, bumped bodies, a single eye-stalk protruding from their head, and an energy weapon built into their frame. They are the Daleks, one group of survivors of a nuclear war that destroyed the planet. Driven underground and into their robotic tanks, the Daleks have become hostile towards anything that is not a Dalek - like, for example, the Doctor, Susan and her teachers.
In 1965, the same thing happened, only slightly differently. Dr. Who (Peter Cushing), a kindly old inventor, shows his Tardis (no definite article) to Ian (Roy Castle), boyfriend of his daughter Barbara (Jennie Linden), who is the elder sister of a young(er) Susan (Roberta Tovey). Ian accidentally activates Tardis and sends the group to a bizarre planet, with a petrified forest and an empty city. There, they discover that they've been exposed to dangerous amount of radiation, but before they can return to Tardis to escape, they are captured by the Daleks - robots with colorful, domed, bumped bodies, a single eye-stalk protruding from their head, and a gas weapon built into their frame. They are the survivors of a nuclear war etcetera, etcetera, etcetera.
The first story - the 1963 one - is simply entitled "The Daleks". It is the second story in the Doctor Who television series, and introduced two of the concepts that would come to define the show's 47-year old (and counting) legacy: the TARDIS' unreliable navigating mechanisms and the Daleks, the merciless, brilliant, adversaries of the Doctor.
The second story (1965) was released as a theatrical film entitled Dr. Who and the Daleks, and directed by Gordon Flemyng. Based on "The Daleks", it is the first Doctor Who story to be told in color and in widescreen. The television show would not show its first episode in color until 1969, and widescreen would have to wait until 2005. However, the movie made such dramatic departures from the television series that it was never considered part of the official continuity. This, as it turns out, is both good and bad.
The reasons why it's bad are obvious: while the television series had a mysterious anti-hero as its protagonist, the film gave us Dr. Who, a lovable, bumbling, grandfatherly inventor, just like every other lovable, bumbling, grandfatherly inventor who had come before or after him. Some changes are innocuous, such as reducing the TARDIS to Tardis. Other changes, however, are far more grievous: for example, changing the main character from an alien only known an "the Doctor" to a human being with the actual surname of "Who". The second probably made sense in the context of a movie franchise, but it sucked the soul out of what makes Doctor Who unique - having an enigmatic, cryptic alien as the hero.