He unbars the gate and steps through. Beyond the priory walls the dawn is already a pale presence in the east and the snow lying over the fen gives off a light so cold it is blue. To the south, where the river curls around itself, the millwheel is frozen in mid-turn, as if opening its mouth to say something, and beyond it the bakery, the brewhouse and the lay brothers’ granges stand deserted, their walls frosted, their roofs bowing under the weight of snow. Nothing moves. Not a thing.

Then the fox screams again, high and sharp. Thomas shudders and turns back to the gateway, as if he might somehow be allowed back in to return to bed, but then he collects himself and turns again and forces himself to move. One step, two, carefully keeping close to the priory walls, following them around to where the dark line of the old road comes into view on its way through the fen towards Cornford and the sea beyond. There was a time when it might have been busy, he thinks, even on a morning such as this. Merchants might have been making their way to Boston with their wool for the fleet sailing for the Staple in Calais, or pilgrims might have been coming to the shrine of Little St Hugh in Lincoln. These days though, with the land so lawless, anyone abroad at this time of day is either a fool or a villain, or both.

By the time he reaches the sisters’ cloister Thomas’s shins are scorched, his chilblains throb and his fingers are already so thick and clumsy with the cold he knows he will not be able to hold a quill all day, knows he’ll make no progress with his psalter. Even his teeth ache.

He stops at the sisters’ gate, pauses a moment, glances at it though he knows he must not, then he leaves the shadow of the priory’s wall and cuts away, down across a field where the lay brothers will plant rye in the distant spring. There is an old path on the snow, a line of footprints he follows through the furlong and down towards the dung heap by the river. Here the path ends in a confusion of dimples in the snow and broken ice, as if someone has been fetching water.

Thomas climbs down the low bank on to the ice where a mist unfurls around his ankles. He steps on to it, testing it though he knows it to be strong enough to bear a cart and ox, and he hurries across in a few quick strides to thread his way through the ice-rimed reeds on the far side. Just as he is scrambling up the bank, the fox shrieks once more, rough-edged, filled with pain. Thomas pauses, frozen. The scream stops abruptly, as if cut off.