I stand at the edge of the river and peer across it, while Anna stays a few feet back, her hands in her pockets, her chin dipped. She is tense and watchful. Unsurprising, I suppose.

She joins me and points to a shallow inlet. Grasses and leaves wave languorously, caught at the edge. The water ripples but it isn’t flowing particularly fast. Last night, after Anna gave me the address, I looked the house up on Google Earth and zoomed in on its surroundings. The river meanders through miles of farmland, then broadens, winding snakelike until it reaches Dartmouth where it spreads and empties into the sea. It’s a long way for a body to travel. Surely if Nick had decided to drown himself his body wouldn’t have made it far? Someone, a rambler perhaps, would have found him.

Anna looks around and seems confused, as if she’s expecting to see something that isn’t there. Is Izzy so vivid in her mind that her subconscious is looking out for her? She strides forward, then stops. I follow her to a muddy spot where the ground drops into the brown water less abruptly.

‘This is where Izzy went in, where her shoes were found,’ Anna says. ‘We swam here. Izzy wasn’t allowed unless there was an adult with her because she wasn’t a strong enough swimmer. She had weak lungs and her heart had been operated on when she was a baby, so she wasn’t supposed to over-exert herself. The problem was, she was determined to do everything we did, not to be the wimp.’

‘She sounds like a feisty little thing.’

‘She was. The current can be strong when the tide changes and the Dart gets sucked towards the estuary. It was pouring with rain that day. And after heavy rainfall it can rise suddenly and become much more dangerous.’

‘How far downriver was she found?’

‘About a mile. She … She was caught on a fallen tree.’

The image is so unbearably sad that my throat constricts as I try to hold back the tears. Izzy Wells wasn’t much older than Lottie. I wipe my eyes and blow my nose on a tissue I find in my pocket. ‘Why do you think she came down here?’

Anna looks away. ‘There could be any number of reasons. She was bored. She wanted to prove something. Someone upset her.’

Nick? I wonder about that, but I can’t imagine it.

I don’t want to leave the spot I’m standing on. There is a strange force keeping me here, weighting my feet to the wet earth. I think about Izzy taking off her shoes and wading in, getting out of her depth, the currents wrapping around her slim child’s body and dragging her down and along. It must have been terrifying. Is that what happened to Nick?