IT WAS WHILE walking her shih-tzu, Pearl, in the park that Gretchen Doyle first realised she was a witch.

She had just entered the shade beneath the trees when she heard a faint meowing from above. Gretchen stopped and looked up, blinking against the spots of bright sunlight that poked their way between leaves.

She saw the cat, smoke-grey with dark stripes, crouched on a high branch overhanging the path. It stared at her with black-hole eyes, and its meowing grew louder and more pitiful.

‘It’s all right. Just stay there,’ said Gretchen, wondering what to do.

The cat scrambled along the branch, claws splayed and scratching as it tried to run and cling at the same time.

This didn’t count as staying there, and Gretchen’s mouth dropped open, but the tip of her tongue knew no words.

The cat’s hindquarters slipped from the bough, and with a plaintive Miaaaow it hung there, gripping the bark.

Gretchen sprang forward.

The cat dropped.

She raised her arms instinctively to catch it. But the cat was no longer falling. Suspended in mid-air, it regarded her calmly. Gretchen stared back, too bewildered to form any proper thoughts; yet she sensed that she was somehow in control, and so, inch by inch, she lowered her hands, and the cat wafted on to the path.

Pearl, head cocked on one side, gave a single yap. The cat paid no attention, but sat down and continued to look at Gretchen with a serenity that seemed all wrong, a satisfied smile playing at the corners of its mouth. As though the whole thing had been a performance.

‘Stupid,’ Gretchen muttered, then added, as firmly as she could, ‘Well you’re safely down now, so that’s good,’ even though good seemed an unfit word to describe what had just unfolded. ‘Come on Pearl, we have to go.’ She clipped the dog’s lead on to her collar and resumed walking along the path – well, striding really.

Her mind, overwhelmed, had triggered its own safety mechanism by going completely blank; nonetheless, the urge to glance over her shoulder was very strong.

The cat was following them.

Gretchen hurried through the park, into the streets, and all the way back to her house. As she turned her key in the front door, she stopped, sighed, and turned to look behind her. The cat was sitting on the garden path, expectant.

She opened the door and went inside, and her new acquaintance followed.

For some time, Gretchen sat at her kitchen table, pressing her palms to the tabletop as though afraid of what they might do. She had given the cat a saucer of milk, and watched now as it lapped it up delicately. Curiously enough, at this moment it was Pearl who bothered her most. The shih-tzu was a notorious chaser of cats, but she had made no move to pester this one, and was currently snoozing by the fridge-freezer. This one she was treating in the same way she would a visiting human.

Gretchen stood and went out into the back garden. She passed a watering can over her large and leafy vegetable patch, and her window boxes brimming with herbs, and she tended the tomato plants in her greenhouse. All the while, she left the back door of the house wide open, hoping her guest would slip out and disappear.