Dealing with time travel, the story bounces back and forth between Claire meeting Henry at different ages, out of order, as she grows up. Executive producer and writer of the series Steven Moffat has some experience telling stories out of time, having been the showrunner on Doctor Who. “I don't think out of sequence is as difficult as people think it is,” he explained to SciFi Vision during a recent roundtable. “I think our memories work like that anyway. I mean, the story of your life is stored in your head. You know the story of your own life. Is it in sequence? If you think about your life, do you think of day one, day two, day three? No, you face a whole jumble of events that are ordered by priority or interest that are linked together, because they're about the same thing or happened in the same place. The story of your own life is nonlinear. Your life is linear, but the story of it is a mess, and, frankly, it would take you days to try and work out in what order anything happened…So, in a way, stories are like memories. There's a chaos of events, and the links between those events are about the subject or emotional or their context.”