I understand that the faster one goes the slower time goes but a thought popped into my head recently that I couldn't resolve; Alice and Bob are at rest relative to each other in an otherwise empty universe (i.e no point's of reference). Suddenly Alice observes Bob moving away from her at .99c. Twenty years later Bob returns having flown away for a decade before turning around. According to my calculations 20 years at .99c would last only 2.8 years for the traveller. My confusion comes when I consider the fact that in Bob's point of view it is Alice who has moved away at .99c for ten years before coming back. I was under the impression that there were no privileged points of view. So in this scenario when Alice and Bob meet back up whose clock would say 20 years and whose would say 2.8 years and why?