Clara dear, it's me, River Song. The Doctor's wife, I thought you might remember me. I hear that you are the new companion, and while at first I congratulate you on being – chosen - by him, I feel that there are things I must warn you of if you're going to travel with him.
First things first – never question the Doctor. He will tell you if you need to know.
Second – if he says run, you probably should.
Third – things are going to get strange. You'll start to think you know people that you know you haven't met before, that's because you've probably met them already, but in the future, so technically you still haven't met yet... Timey-wimey, as the Doctor says. What a ridiculous phrase, but ever so accurate.
Fourth – he is a terribly old man, over a thousand years old now. There isn't anything he hasn't seen, done, or at least heard of. He always knows what to do, even if it doesn't seem that way. So trust him with your life.
Fifth – don't trust him with your heart. Don't fall in love with him. It will be your undoing.
Most importantly, and I don't mean this to sound jealous or manipulative in any way; don't let him fall in love with you. I will be gone quite soon, and he won't remember me at all. Look after my silly Doctor for me when I can't.
I've written you eleven letters, guiding you through your companionship. I've already seen where you're going with him and what's going to happen, so I thought it might do well to help you through them.
Regards,
Professor River Song.
P.S: You won't remember me after you've finished reading the last one.
P.P.S: Fish fingers and custard are excellent, trust me.
P.P.P.S: The Doctor has met you many times before, you just need to remember.
P.P.P.P.S: Spoilers, sweetie.
