So, still reading Crace's The Pesthouse - I'm only reading it of a night whilst sweating it out in a hot bath... you didn't want to know that!
And I came across an interesting way in which Crace conducts his two lead characters. As I predicted previously, when Crace made it quite clear he was giving us a future reference the female lead wouldn't know yet, she'd see the male lead again... and she does, as the story heads towards the dying days of the second act.
Up until this point we stick with the female lead, Mags. Note, it's the male, Pigeon, who was kidnapped for manual labour, and so it is him who'd we, the reader, would be more worried about as we stay with Mags's story. Crace builds in this two-level suspense. Underlying all of Mags's trials we, knowing full well that we will meet up with Pigeon again, worry about where and when, and how he is.
We follow her story, right up until the point where she meets with someone directly related with Pigeon - the man who kidnapped him and stole his one-of-a-kind coat (don't worry, it's not Joseph and that darn Technicolour dreamponcho). And there, with the badguy starting to cause murder and mayhem, and just when Mags's has been put into danger...
We leave Mags's and join Pigeon. We start a new chapter, open with a brief paragraph on the now, and then leap back to that night when he and Mags were split - note that we don't have the time and possibly not the inclination to go into as much depth on Pigeon's time as we did on Mags, so it is fairly condensed. Crace provides the right information to give the flavour of the characters Pigeon is with.
Once we are brought back up to speed with the now, Crace pulls Mags into view with Pigeon and merge their tales again.