I am obsessed with River Song.
You have no idea who that is, do you? Sigh.
River Song is a character in Doctor Who. She is marvelously portrayed by Alex Kingston, who has lovely mad curly hair. She is fantastic in the role.
When we first meet her, she is on a planet called The Library. (It's a planet-sized library, go figure.) She has somehow managed to get a message to the 10th Doctor (the fine actor David Tennant) requesting his presence, even though he has no clue who she is.
As it turns out, she is someone from the Doctor's future.
Hmm. Perhaps I should back up. The Doctor is the last remaining member of his species (with the occasional exception). He is a Time Lord. He appears human (or, as he would say, humans appear Time Lord, since they came first). He is a time traveler genius who tries to protect the innocent and do the right thing. His time machine/spaceship is called the Tardis, and it looks like a blue British police box, but it's bigger on the inside. And he typically has a human companion with him, someone he likes who he wants to show around all of space and time.
Back to River Song. Ah yes, she is from the Doctor's future. So she knows him, but he does not know her. And this is obviously very painful for her, though we don't entirely know why. Obviously, the Doctor is personally important to her - the implication is that she loves him, though it's not yet clear whether this is romantic or familial or some other kind of love.
Let's stop right there. Can you imagine someone very important to you - perhaps the most important person in your life - and bumping into them, but then they have no clue who you are? And not like an Alzheimer's patient, where they might have a better day and recognize you, but meeting someone and knowing everything about how much they mean to you and realizing that none of that has happened yet for this person? And how painful it must be to not be able to change things that you know will hurt them in the future, because for you it has already happened?
That notion is why I'm obsessed with River Song. Full Stop.
There are other cool things too though. She is not a pacifist. In fact, she's sort of a badass, a cross between Lara Croft and Indiana Jones. Smart enough to keep up with the Doctor, but not the kind of person who shys away from danger or adventure. And the Doctor doesn't seem to mind her occasional violence, which is slightly unusual for him.
Also, being from the Doctor's future, she knows a lot about what is to come. Not necessarily in the current situation, but adventures that she has already experienced and the Doctor has not. She keeps a diary of their time together, so she can establish "when" he is, and what she is able to discuss with him freely. (Avoiding "spoilers.") Likewise, as things progress, the Doctor knows about his past/her future. It is a great big fascinating tangle.
I don't want to give away plot points. There is a lot of mystery around River Song's origins and how well she knows the Doctor. The answers have not all been provided as yet. But I'm very much looking forward to how things resolve.
If this sounds cool to you, go watch "Silence in the Library" and "Forest of the Dead," which are the two episodes set in the Library where you first meet River Song. They are a great place to start watching Doctor Who, and what hooked me on the series.