After turning down the Doctor’s offer to travel with him after her disastrous non-wedding, Donna had doubted she’d ever see him again. Maybe she’d blown her one chance of seeing what was out there in space, beyond the world she knew.
Still, just meeting him had opened her eyes to the fact that there was so much more to life than soaps and reality TV.
So here she is, sneakily investigating the new miracle weight loss drug. It seems too good to be true; there’s something fishy going on. And look who’s here, doing exactly the same thing!