The heads of the herd are almost at the other side. She watches, breathless with a triumph for which she has no words, as the first bull reaches the shore, his tail twitching and his hooves stomping off the wet. The others gather behind, but he does not wait – the path is narrow and leads through the forest, and soon he disappears behind the pines.

The stragglers are cows with young calves. The distance between them and the herd grows by the second, and as she pushes off the boulder to swim closer she hears a sound, a cry, that is at odds with the majesty of this scene. A child’s cry.

Her heart hammering, she sweeps her arms through the water and kicks her legs until she is only feet away from the last of the herd, the two dozen or so calves and cows that stray behind the rest. As one of the cows moves forward she sees something that makes her cry out, that makes her heart almost punch through her chest: Gaia is swimming there, her small blonde head foreign amongst the animals, her pale face ducking above and beneath the water.

‘Mumma!’ she calls out. ‘Mumma, help!’

‘Gaia!’

Aurelia’s body floods with adrenalin as she surges forward. Already her mind is wheeling calculations. They’re about a quarter of a mile from shore, and her energy is ebbing. The water is cold and Gaia will not last long. She’ll take her back to the boulder, but when she glances behind to gauge the distance she is horrified to see that the boulder is no longer there. The waters have somehow deepened, and she is much further from shore than she thought.

She powers forward towards Gaia, seizing her by the hair just as she begins to fall under. She wraps her arms around her and holds her, their wet faces pressed cheek to cheek, both bodies shaking with terror and cold.

‘Mumma,’ Gaia says weakly, and Aurelia urges her to keep kicking her legs, to stay awake, not to fall asleep.

‘Please, darling,’ she says. ‘I know you want to go to sleep so badly, but you have to try to stay awake, OK? I’ll get you that dolls’ house you wanted. You have to try, Gaia. Please!’

Gaia gives a faint murmur in response and wraps her arms around Aurelia’s neck, but her grip loosens, and Aurelia is forced to swim with one arm, using the other to hook Gaia’s face up out of the water. She sweeps and sweeps the water, dragging them to the shore, but the mist is thickening again and she can’t see where she’s going. She’s trying desperately to draw on adrenalin and reserves of certainty. If she panics her energy reserves won’t last, and if that happens, it’s over.

‘Nearly there,’ she tells Gaia. ‘Nearly there.’