“Everyone does,” said Bunny, with assurance.

“Don’t be silly!” said Toby.

They were past the slit in the wall, and were winding upwards now towards another.  Bunny postponed argument, finding he needed all his breath for the climb.  The steps had become narrower and more steeply spiral than before.  His companion mounted so swiftly that he found it difficult to keep close to her.  The ascent seemed endless.

Again they passed a window-slit, and Bunny suddenly awoke to the fact that the flying figure in front was trying to out-distance him.  It came to him in a flash of intuition.  She was daring him, she was fooling him.  Some imp of mischief had entered into her.  She was luring him to pursuit; and like the whirling of a torch in a dark place, the knowledge first dazzled, and then drew him.  All his pulses beat in a swift crescendo.  There was a considerable mixture of Irish deviltry in Bunny Brian’s veins, and anything in the nature of a challenge fired him.  He uttered a wild whoop that filled the eerie place with fearful echoes, and gave chase.

It was the maddest race he had ever run.  Toby fled before him like the wind, up and up, round and round the winding stair, fleet-footed, almost as though on wings, leaving him behind.  He followed, fiercely determined, putting forth his utmost strength, sometimes stumbling on the uneven stairs, yet always leaping onward, urged to wilder effort by the butterfly elusiveness of his quarry.  Once he actually had her within his reach, and then he stumbled and she was gone.  He heard her maddening laughter as she fled.

The ascent seemed endless.  His heart was pumping, but he would not slacken.  She should never triumph over him, this mocking imp, this butterfly-girl, who from the first had held him with a fascination he could not fathom.  He would make her pay for her audacity.  He would teach her that he was more than a mere butt for her drollery.  He would show her—­

A door suddenly banged high above him.  He realized that she had reached the top of the turret and burst out upon the ramparts.  A very curious sensation went through him.  It was almost a feeling of fear.  She was such a wild little creature, and her mood was at its maddest.  The chill of the place seemed to wrap him round.  He felt as if icy fingers had clutched his heart.

It was all a joke of course—­only a joke!  But jokes sometimes ended disastrously, and Toby—­Toby was not an ordinary person.  She was either a featherbrain or a genius.  He did not know which.  Perhaps there was no very clear dividing line between the two.  She was certainly extraordinary.  He wished he had not accepted her challenge.  If he had refused to follow, she would soon have abandoned her absurd flight through the darkness.

It was absurd.  They had both been absurd to come to this eerie place without a light.  Somehow her disappearance, the clanging of that door, had sobered him very effectually.  He cursed himself for a fool as he groped his way upwards.  The game had gone too far.  He ought to have foreseen.