Once upon a time there was a girl who lived in a dream. She listened to the opera Carmen and burned soufflés.
But her dream was also a nightmare. Until she met that man. She saved his life and it wasn't the first time she met and saved him. However, that's a long story and it begins at the end.
The girl got shipwrecked in the Asylum of the Daleks and they came for her every night. She'd been there for a year fighting against them. This was her nightmare. Only one day this man appeared. The Doctor. He promised her to get her out.
"Rescue me chin-boy and show me the stars, " she said to him. But they both had to realize that all around her wasn't real and that she was already converted to a Dalek. She helped the Doctor and his friends to escape the Dalek Asylum and also she erased him from all records in the universe. And she died.
What the Doctor didn't know was that he would meet her again. He met her in Victorian London where she was a barmaid and a governess. And again she saved his live and died. Then he went to find her and he did. He found that girl again. Clara Oswald. Oswin, the soufflé girl. Impossible Clara. That's how their story really begun.