When a troubled person sends Duke and Nathan back in time to Haven 1955, they meet Sarah Vernon. She is a nurse who had just arrived to Haven to take care of an ex-soldier. Nathan and Sarah immediately click and they share a very intimate afternoon on the beach (as well as several kisses). The big question here is if something else happened between them that could make us wonder if Nathan is the Colorado Kid's father or not. Sarah never told anybody who the father was but he is our best (and I guess only) suspect.