‘Sensibilities,’ she says, trying out the word and liking it. She adopts a sibilant hiss, moves her head, snakelike. ‘Thenthibilitieth …’

They sit in silence for a time. Taste the air. Hold one another. Watch the rain create countless overlapping circles on the surface of the water. On the other bank, hidden among the bracken and nettles, the sap of the birch tree oozes through the metal cylinder and into the small glass container. Over the last few weeks, the pair have made numerous trips to remote parts of the countryside. Seeking out specific hedgerow flowers, grasses, funguses and spores. She consults no textbook or journal. Just tells him when to turn left, and right, and where to park, and holds his hand as she leads him down overgrown tracks and tangled glades, seeking out scents, flavours; some quality in the air. Today it’s birch. The leaves will serve as a painkiller and the sap, taken as a cordial, is a diuretic. An unguent distilled from the twigs and leaves eases rheumatism and joint pains. Her father had requested the potion when last they spoke. The weeks hiding out had taken their toll on him and his brothers. He was feeling his age. Roisin had been thrilled to do something of use, and has fallen back in love with the herbal medicine she learned from older family members as a girl. Already she has transformed the house on Exmouth Street into something more akin to a witch’s pantry. DC Buller moved out three days after Roisin moved in. He’d been a bit awkward; a little embarrassed, but he’d given McAvoy the closest he’d ever had to a manly punch on the shoulder and called him a ‘sly dog’ who was ‘punching way out of his class’. McAvoy had glowed crimson. Roisin had laughed like a drain.

‘Valentine …’ says Roisin, unexpectedly.

‘Sorry?’

‘My brother. He’s asked if he can be best man.’

McAvoy laughs, bemused at the absurdity of the suggestion. ‘He’s ten!’

‘Eleven …’

‘I barely know him.’

‘You barely know any of us.’

‘And it’s just a small wedding, isn’t it?’

‘Did you have anybody in mind?’

McAvoy chews his cheek. He hadn’t even given it any thought. He doesn’t want sympathy over the fact he has no real friends, but he’s aware his side of the church is going to look a little empty. His mother told him she would be unavailable even before he suggested a date. His dad and brother, both sounding more than a little sceptical, had told them they’d do their best to be there but could make no promises. His old sergeant from Cumbria Police is more of a mentor than a friend and at work he’s seen as the odd, shy giant who came back from a family emergency with stitches in his face.

‘He likes you …’

‘Well, that’s nice to know, but …’

‘Thank you. He’ll be thrilled.’

Aector chews his lip. Holds her close. Shivers in his wet clothes and feels her grip tighten on his arm.