Perfect Stranger Movie Who Is The Perfect Stranger From The Perfect Stranger Movie?

Who is the perfect stranger from the perfect stranger movie? - perfect stranger movie

I do not understand.
I'm confused.
So, who is abroad in the film, is the daughter, Ro
or is your friend Mike?

and also, it was Grace, the girlfriend of Mike?
Grace was the one who said Mike Ro secret?

I hope this does not sound very confusing.
Thank you in advance.