From Storm in Heaven:

Koizumi Kanna is infatuated with the man who came to the restaurant she works at and ordered a burger with no onions. Little does she know, Toujou Ren is interested in her as well, but for a different reason. Kanna just so happens to be the mirror image of a woman he knew a very long time ago. It is for that reason that he saves her when she nearly dies in a car accident. But the life he gives Kanna is far different from the one she lived before, and she's not certain it's the kind she wants...