A few years ago... there's a main male protagonist but he is part of a small group of people who live their same lives over and over. The opening chapter is about when he is dying in hospital and a young girl comes to see him (she's also one of these people) to pass on a message from the future that he'll then be able to pass back when he's reborn. This is system they have - to pass messages back and forward through time.
There are people looking to 'seek and destroy' this group of people I think. Also at one point he gets involved in some nuclear power project with someone who's a bit of a maverick and he's not sure he can trust... it's driving me mad please help!