As she nears the top, she shudders involuntarily. There’s a musty smell in the air she can’t place. A sudden memory of locking the front door comes to her. She hung the key in the kitchen before making up Charlie’s last feed. So how could it have opened? For a few moments she stops, one foot on the top stair. Can a newborn sleep so long without food? She takes a deep breath and tiptoes into the room, but in the dim light she can see the crib is empty.

She blinks hard and turns on the bedroom light, staring at the stark white cotton sheet as if he will appear, but shadows of the bulb jump in front of her eyes. The teddy she bought when she first became pregnant is still at the bottom of the crib. The sheets are pulled back, as if she’s taken Charlie out. Did she? She is so dazed she can’t remember. Traces of his downy hair where he turns his head from side to side are on the flat pillow. The new cotton blanket she bought last week has been dropped on the carpet. Two cupboard drawers are hanging out, empty. Charlie is nowhere to be seen.

She scrabbles around on her knees hoping by some bizarre miracle that he’s fallen out. But he’s not there. She clutches her throat; it is so dry and barbed she’s finding it hard to swallow.

‘Jamie!’ she croaks and bursts into his bedroom.

He bolts up in bed, squinting at her.

‘Charlie’s not in his crib.’ She hears herself scream the words but it’s like they are being spoken by someone else. Her face is burning, eyes bulging. ‘Is he here? Did I leave him with you?’

‘What do you mean? He’s not here.’ He scratches his head.

‘Where is he? Where’s he gone!’ Back in her bedroom, Alison grabs the house phone and dials 999.

‘Which service do you require?’ asks the operator.

‘Police please, please hurry.’

Jamie is standing in the doorway, his hands lodged in his messy hair, grasping at the roots. ‘Where is he, Mum?’ Tears fill his eyes.

‘I don’t know, Jamie, I just don’t know.’ Her whole body is shaking. She grips the phone with both hands. ‘Think, try and think where he could be.’

The operator asks where Alison is calling from and takes her details.

‘Please help me, you must help me, I can’t find my baby, he’s gone, oh my god, he’s gone!’

‘Okay, I need you to sit down, and take a deep breath. Can you tell me what baby’s name is?’

‘Charlie, his name is Charlie Wood.’

‘And is there anyone else in the house with you?’

‘Yes, my eight-year-old son, Jamie,’ she reaches out and grasps his hand.

‘And where was Charlie before you went to sleep?’