He saw two horses: one white and the other black. A moment later, though, he noticed in horror that the white horse had a spirally twisted horn on its domed forehead. He also saw that a girl was sitting on the black, her ashen hair combed so as to obscure her cheek. The group apparition seemed not to be touching either the ground or the water–it looked as though it were suspended above the fog trailing over the surface of the lake.

The black horse neighed.

‘Whoops…’ said the girl with the grey hair quite distinctly, ‘Ire lokke, ire tedd! Squaess’me.’

‘Saint Ursula, O my patron…’ mumbled Hasso, white as a sheet. The crossbowmen froze open-mouthed, and made the sign of the cross.

Von Schwelborn also crossed himself, after which with a trembling hand he drew a sword from a scabbard strapped under his saddle flap.

‘Heilige Maria, Mutter Gottes!’ he roared. ‘Steh mir bei!’

That day Sir Heinrich didn’t shame his valiant ancestors, the von Schwelborns, including Dietrich von Schwelborn, who had fought bravely at Damietta and was one of the few not to run away when the Saracens conjured up and set a demon on the crusaders. After spurring his horse and having recalled his fearless forebear, Heinrich von Schwelborn charged the apparition among the fresh-water mussels splashing up from under his horse’s hooves.

‘For the Order and Saint George!’

The white unicorn reared up like a heraldic emblem, the black mare danced, and the girl was alarmed, it was clear at first glance. Heinrich von Schwelborn rode on. Who knows how it all would have ended if the fog hadn’t suddenly been blown towards him and the image of the strange group dissolved, disintegrating into a myriad of colours like a stained-glass window smashed by a stone. And everything vanished. Everything. The unicorn, the black horse and the strange girl…

Heinrich von Schwelborn’s steed rode into the lake with a splash, stopped, tossed its head, neighed, and ground its teeth on the bit.

Hasso Planck, struggling to control his unruly horse, rode over to the knight. Von Schwelborn was huffing and puffing, almost wheezing, goggled-eyed like a fast-day fish.

‘On the bones of Saint Ursula, Saint Cordula and all the eleven thousand virgin martyrs of Cologne…’ Hasso Planck stammered out. ‘What was it, noble Herr Ritter? A miracle? A revelation?’

‘Teufelswerk!’ von Schwelborn grunted, only now blanching horrifyingly and chattering his teeth. ‘Schwarze Magie! Zauberey! A damned, pagan, devilish matter…’

‘We ought to get out of here, sire. As quickly as possible… It’s not far from Pelplin, anything to get within the sound of church bells…’

Sir Heinrich looked back for the last time on a rise just outside the forest. The wind had blown away the fog and the shining surface of the lake had grown dull and rippled in the places not obscured by the wall of trees.

A great osprey circled above the water.