And he’d looked up at her and said, ‘Has Dad gone yet?’

A simple, innocent question. So why did it strike a terror into Katie’s heart that made her hold her breath? ‘No lamb, he’s still here. You can see him before he goes to work.’

Billy had leapt to his feet and yelled, ‘No!’, before running back into his room and slamming the door. She’d heard him sobbing behind that wooden door, and had stood looking dumbly at the wooden barrier between them, with its poster of Sonic the Hedgehog grinning malevolently back at her with a two-fingered salute.

Sam had looked concerned when Katie returned to the kitchen, but accepted her explanation that Billy wanted to be left alone.

Would he have accepted that a month ago? Or would he have been up there poking his son in the ribs and asking what was up? Sam had looked like he was someplace other than the kitchen, so she’d let it be, battling back her darkest fears and misery as she watched her coffee go cold. And the three of them, Katie, Sam and Jess, had sat in a silence broken only by Jess’s occasional babbling, until Sam had left the house.

Billy had heard the door close and had crept carefully and tentatively into the kitchen. It made her freeze, to see her son so desperate to avoid his father. The same boy who would fight to accompany Sam to the bathroom if he let him. Could a dream be so real? And what had happened in that dream?

Katie Hunt was adrift, and it felt bad. Today, Sam was like a stranger trying to be her husband. He said the same stuff he usually did, smiled at her from time to time with those white even teeth and kissed her when she came to pick him up and drive him to the doctor. But it wasn’t Sam. Or more accurately, she wished it wasn’t. Her Sam didn’t lie, or frighten their son, or look hunted and dark when he thought he was unobserved.

She could feel him now, trying to catch her eye in this small beige surgery, and yet she couldn’t turn to meet his gaze.

‘Okay, I’m just gonna prick the sole of your foot here. Just relax.’

Sam braced himself. Doctor Alan Harris did the business, made an uh-huh sound, and put Sam’s foot gently back down on the vinyl bed he was lying on. ‘Okay, Mr Hunt, you can put your shoes back on. What I’m going to say is that I want you to get checked out by Neurology in Calgary.’

Katie sat up and lost interest in the opaque window. She uncrossed her arms and leaned forward.

Her action had the effect of making the doctor turn to address her, as though Sam were a child in her care.