Do you have an identical twin sister?
No? It's okay, most people don't.
But if you did, would you switch places with her?
Of course you would - when you were five.
You might even do it again when you were fifteen.
But a twin switcheroo at twenty-six?
This won't end well.
Add in a sexy stranger - with an even sexier British accent - and things are about to get really complicated.