If you are not from the Planet Ming Mong, then here's a run down on Dr. Who:
He is an alien. He's a renegade bad boy Timelord from the planet Gallifrey, who has a soft spot for the human race and spends a lot of his time rescuing them. He can regenerate himself, and each reincarnation has its own personality traits & quirks. (Tom Baker by far and away was one of the best and best loved as the fourth incarnation. David Tennant is pretty popular too, he played the Tenth Doctor.) He travels through space and time in his space/time machine, the TARDIS = Time And Relative Dimensions In Space. He carries a sonic screwdriver. This incarnation's personality is "partial to tea and muffins", wears a long dramatic scarf and an overcoat with lots of pockets, has a robotic dog named K-9, and breaks the ice with complete strangers by offering them Jelly Babies.
This story is classic Tom Baker/Fourth Incarnation. I must have watched this one on VHS a hundred times as a kid. Heh heh, and an adult. I finished reading this back in November; incidentally the same day the Bear and I went down to the county courthouse in hoodies and got married. Yep, I was reading Doctor Who on my wedding day. Typical of the Doctor, this adventure starts out by a chance encounter. He is taking his companion Sarah back to the real Earth and when the TARDIS malfunctions slightly, they accidentally stumble into a hostile "aliens using androids" take-over attempt of the Earth by the Kraals where he goes head to head with the Chief Scientist of the Kraal Expedition, the Doctor and Sarah are both put in a bunch of sticky situations that they have to get out of by quick thinking, there are creepy androids, scary militant aliens, and the wonderful & clever Fourth Doctor...love everything about this story! If you are a Who fan, this is a classic you must sample. If you're not a Who fan, it means you haven't met the Doctor yet and you need to.