When flight Air France 006 enters a terrifying storm, the plane – inexplicably – duplicates. For every passenger on board that day, there are now two – a double with the same mind, body and memories. Just one thing sets them apart. One plane leaves the storm in March. The other doesn’t land until June. For world leaders, the emergence of the June flight raises serious alarms. No science, faith, or protocol can explain this unprecedented event. But for the passengers, a bigger question is at stake. What happens to them, now that their life is shared? What happens to those who land in June, when their March doubles make decisions that will change their lives forever? And as the doubles prepare to meet, they have an extraordinary decision to make. If there are two of them, and just one life – who gets to live it?