iv. James Robertson takes the baton from Toby Litt in Hamish Hamilton's game of literary consequences

You look at the blonde waitress, raise your eyebrows and give the tiniest shake of your head, as if somehow these gestures might be enough to persuade her to take you into her confidence. Maybe they are. She twists one side of her mouth – the shape is called a wry smile – to indicate that she appreciates your sympathy. She understands, too, without you having to ask, that you want a coffee. You pull yourself up on a stool at the bar, and she brings you the coffee, black in a plain white cup, with a small cellophane-wrapped biscuit resting in the saucer. You notice her hands – the slender, frail-looking fingers that don't seem suited to the work she does. You say, 'So tomorrow, this cafe won't be here?'

'Don't worry,' she says. 'This is not the first time he comes in. Always the same. Only some days he wants to buy the jukebox, others he wants to buy the cafe. He's a little mad, I think. But we're all a little mad.'

You like her. She has noticed you after all. And then, glancing down at the bar, you notice something too, a small leather wallet, the kind you might keep cards in. Calling cards, credit cards, an ID card. You reach for it, feel the familiar bulk of plastic oblongs inside. You flick it open. His face stares out at you with panicky eyes, as if he did not expect to see you, as if the camera took him by surprise.

The waitress has moved away but when you say, 'Hullo,' she hears you at once and comes back, smiling. You hold the wallet open at the ID card, like a cop on a door-to-door inquiry, and say, 'Georg Schmidt.'

'Oh.' She looks concerned for poor old Georg. 'But I cannot leave the cafe.'

'Don't worry,' you say. 'He'll come back.'

'No, perhaps not.'

You shrug. She gives you a pleading glance.

'He is a little mad. He will be lost out there without this.'

'You want me to...?'

'He won't have gone far.'

'It's New Year's Eve. Hogmanay, back in the old country. There's snow in the air. You remember going round the village, first-footing the neighbours, everybody cheery and wanting a kiss and a song. A long time since... You remember how lost you felt in that cosy, claustrophobic comfort, how you had to get away into the kinder anonymous wastelands of the world. But you can't help feeling the waitress is right – or maybe you just want her to be right because you like her, and you want her to like you: so, yes, out there, Georg Schmidt will be lost.

'If you keep my seat for me,' you tell her, 'I'll go after him.'

You look for gratitude in her eyes, and something more than that, and you reckon you see it. You think of her smile when you come back in from the cold, mission accomplished, the madman reconnected with his picture.

You pick up the wallet containing Georg Schmidt's identity, and you step out into the darkening street. And as you go, some voice in your head is saying: this is a good, a decent thing you are doing. But you don't quite believe it.

The Testament of Gideon Mack, by James Robertson, is out now in Hamish Hamilton hardback   Read more