The Sarah Jane Adventures, CBBC (UK)
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This is sort of a spin-off of the revival of Doctor Who. The title character, Sarah Jane Smith, was one of the many travelling companions the Doctor had over the years, back on the original series. But this series was prompted, I guess, from her having guest-starred in an episode of the new series. (Back in 1981, it should be noted, the character also starred in a spin-off called K-9 and Company, which never made it past the pilot.) "The Sarah Jane Adventures began with a special episode called Invasion of the Bane, which aired on New Year's Day, 2007. The series proper began in September of that year. (In the US, the original special aired on April 11, 2008, with regular episodes beginning the next week, on Sci-Fi Channel. But while the show had a run of five seasons in the UK, only the first season aired in the US.)
In any event, Sarah Jane is aware that there are aliens appearing on Earth fairly often, for reasons ranging from visiting, to crash landing, to invasion. Sometimes she'll help them out, and sometimes she has to put a stop to their plans. It should also be noted that this is set in an era where, on the new Doctor Who series, aliens have become known by the general public to exist, though this knowledge hasn't really changed how people go about their lives. It's not like there's official contact or anything, and even now many people still don't believe in aliens. It should further be noted that there exist agencies like UNIT and Torchwood to deal with aliens and such things, though Sarah Jane prefers to handle things differently than they would. For a long time now, she's been alone. She doesn't want to put anyone in danger, and besides, most people wouldn't believe anything she has to say, anyway. But in the pilot special, she met a teenage girl named Maria Jackson, who had just moved in across the street from her, along with her father, Alan (presumably no relation to country singer Alan Jackson). Alan is amicably divorced from Maria's mother, Chrissie, who pops in now and then. Anyway, Maria got mixed up in Sarah Jane's investigation of some aliens called the Bane, and thereafter would help Sarah Jane with subsequent adventures. Also in the course of their first adventure together, the two of them met an apparently teenage boy, whom the Bane had created as part of their plot. But since he's actually brand new, never having been born or raised or anything, he didn't know anything about the world. Though he does have the brain power of like 10,000 people who the Bane had scanned to create him. Anyway, he didn't want to be part of the aliens' invasion plot, so he escaped with Sarah Jane, who "adopted" him, and gave him the name Luke Smith. So now he also joins Sarah Jane and Maria on their adventures.
I should also mention that Sarah Jane has a number of alien artifacts that may come in handy, as well as an advanced, alien computer called "Mr. Smith" (perhaps it's even an AI, I dunno), which is useful for all sorts of things, hacking other computers and whatnot. And in the first regular episode of the series, the team gains another member, Clyde Langer, who goes to school with Maria and Luke. And that's about all I can say so far. I probably saw the whole first season on Sci-Fi, in 2008, but never did have much to say about it. However, I'll re-watch the first season on Amazon, starting in 2018, and then watch the seasons I never had a chance to see before. I expect then I'll have more to say about the show.