‘Hot chocolate?’ Ava asks, looking up at the receptionist then back to Kat. ‘With marshmallows?’

‘My Christmas treat.’ Kat gives Ava her widest smile, and amazingly, Ava smiles back. Kat stretches up, takes the two book bags and Martha’s sports bag from the receptionist without looking at her, then waits to be buzzed out of the school. As the three of them walk across the playground and then out of the gate, Kat wonders if she should ask Ava about Mark, find out what he said to her. But what would be the point? He’s clearly crossed the line, and she doesn’t want to cause Ava any more distress, so they continue their journey in amiable silence.

‘Shall we watch a Christmas movie with our drinks?’ Kat asks as she retrieves the key from Martha’s school bag and slips it into the door. ‘What’s your favourite?’

‘Frozen!’

‘A Boy Called Christmas!’

‘No, that’s too scary. Polar Express?’

‘Yes, Polar Express!’

Kat breathes a sigh of relief at not having to play referee again, then lets the girls lead her into the playroom. They both curl up on the sofa with their hot chocolates (on reflection, Kat imagines Beth wouldn’t approve of hot drinks in here, but she’s not stripping the treat away from the girls now). Ava strokes her cheek with a tatty cloth tiger while Martha picks up two remote controls, and toggles between them until Polar Express appears on the huge screen attached to the opposite wall. Kat has a Netflix account too, but only an ancient laptop to watch it on. It’s not quite the same experience.

Gradually the girls get drawn into the movie, transfixed by the magical train and its northward journey. Kat looks at her watch. It’s been an hour since Beth called her, so it will be another hour before she gets back. Now that Ava seems calm, the itch that she felt yesterday is growing again.

‘Girls, I’m just popping out to the toilet, okay?’

Ava turns her head towards Kat for a moment, smiles, then looks back at the screen. Children appear to bounce back from trauma easily, but Kat knows that’s not the case. Every bad experience nestles itself somewhere, ready to pounce when life gets more challenging. She gives Ava’s arm a gentle squeeze, then slips out of the room, and pulls the door closed behind her. Carefully, she walks up the first set of stairs, then takes the second flight a bit faster.