The concluding half of the story begun in Blackout finds Michael, Merope and Polly still stranded in wartime London, hunting for a way home while the bombs keep falling. Their position is worsening. Polly is working towards a deadline she cannot bring herself to explain to the others, Michael is carrying an injury and a growing conviction that he has already interfered where he should not, and every discrepancy they notice between the war they studied and the war they are living in feeds the same dread. If historians can alter the past, then the Allied victory they have always treated as fixed may no longer be certain, and they may be the cause.
In Oxford, meanwhile, others have begun to notice that three of their people have not come back. Willis moves between the Blitz, the V-1 summer of 1944 and a handful of quieter corners of the war, drawing together threads laid down hundreds of pages earlier and giving her ordinary shopgirls, ambulance drivers and fire watchers their due. The result is a long, intricate and unashamedly emotional account of what heroism looks like when nobody involved can see the whole picture.
