As I go inside, I see the two policewomen sitting at our kitchen table. I know they’re waiting for me – why else would they be here?

‘Niamh? The police want to talk to you again.’ My mother sounds jittery. ‘They say you were with Hollie on one of the days she was missing from school.’

‘Yes.’ I’m not going to lie. ‘But there’s a reason I didn’t tell you.’ I glance at her. ‘Before, I mean.’

Shaking her head, she looks furious for a moment. Then she looks worried. In a flash, I get why. She thinks I know more than I’m saying about what happened to Hollie.

After putting down my school bag, I go over to the table. ‘I made Hollie a promise,’ I try to explain to DS May and Sergeant Collins. ‘Just because she’s dead, doesn’t mean a promise should be broken.’

DS May looks slightly thrown. ‘If Hollie told you something that could help us find out what happened to her, you should tell us, Niamh.’ When I don’t reply, she goes on. ‘So you’re saying Hollie was upset that day? Upset enough that she persuaded you to take the day off school? Wasn’t there anyone else she went to when she needed to talk to someone?’

I shake my head. ‘She didn’t have anyone else. I went to get the bus and she was waiting for me. She was desperate.’

‘So what happened after you didn’t get on the bus?’

‘We came back here. I got changed, and we went out again.’

DS May nods. ‘But first, you emailed your school, telling them you had a dental appointment.’

I pause. Has she rung my school? ‘It was Hollie’s idea. I didn’t want to.’

‘Niamh.’ My mother sounds shocked.

DS May’s eyes don’t leave my face. ‘So what did you and Hollie do after that?’

*

There are things you don’t tell your parents, that they don’t need to know or wouldn’t understand.

‘Please don’t go to school today.’ I found her waiting for me at the bus stop, her eyes huge with dark circles under them, as though she hadn’t slept in days. ‘I’m going mad, Niamh. I need you.’ The words broke out of her in a kind of sob.

I thought about the classes I’d miss, the trouble I’d get into when my mother found out. ‘If I don’t go to registration, they’ll call my mother.’

Her eyes didn’t leave mine. ‘Can’t you tell them you have a dentist’s appointment? I’ll never ask you to do anything like this again.’

I paused, thinking of the school’s online portal for parents. I’d memorised the login details they sent my mother. ‘I suppose I could. What are we going to do?’