Come the night, despite being exhausted, Tilda’s mind is working too fast, trying to make too many connections, for her to be able to rest. An hour before dawn she gives up and gets out of bed. Thistle raises her head and wags her tail.

‘Don’t get up, girl,’ Tilda tells her. ‘It’s silly o’clock. I’m going to make tea.’ But the dog won’t be left behind and pads down the stairs after her. In the kitchen, Tilda puts the kettle on the heat and takes a poker to the Rayburn to ginger it up. The smoldering logs give out more smoke and then splutter into hungry tongues of flame. Staring at the play of orange against gray, Tilda contemplates her next step. She had left the museum disturbed, saddened, and yet encouraged. There was a child. That much is clear. What is equally obvious is that she will get no further tracing the little girl by digging around in the museum archives. She reached the end of that particular trail.

But where else do I search? I’ve tried the records and writing about the Mercian court, but the captives are never mentioned again. There’s a heap of stuff about the queen and what she does, but not a word about the people from the crannog.

A spitting log causes a spark to jump out of the open door. Tilda searches for it on the floor and is surprised not to be able to find it. It was a large, glowing lump of wood, and she is certain it landed by her feet, but it is nowhere to be seen. Following the smell of burning dog hair, she goes to Thistle’s cushion, and is surprised to discover the spark quietly setting fire to the fabric. She picks up the cushion and flicks the little ember back into the fire, musing at how far from the Rayburn it traveled. She rubs at the cloth with her thumb. There is a small hole and a scorch mark but no real damage. Suddenly, something in Tilda’s mind shifts.

Of course! I’m looking in the wrong place! The prisoners aren’t written about by people who documented the life of Queen Aethelflaed because they weren’t with Queen Aethelflaed.

She peers across the gloom of the kitchen. Her laptop is still sitting on the worktop where it has been for weeks.

Could I get that thing to work? I haven’t tried for a while. Could I keep it working? Of course I could. Just an hour or so. Piece of cake.