‘Of course we have!’ Dominic shouts, practically vibrating next to me. ‘And don’t tell me you aren’t already there yourself. We hear it all the time – from every general on every battlefield, no matter whose side they’re on. Humankind can plumb the depths of inhumanity in the name of intelligence. Are you honestly expecting a history lesson on what went on in Northern Ireland, for starters? Christ, the Allies had to let thousands upon thousands be massacred just so the Nazis never worked out they’d cracked Enigma!’

‘And where’s Kayleigh now?’ Olivia’s laser-gaze moves to me. ‘Surely you must still have some connection with her? If it was only ever about her in the first place, and not just what would happen to you? You must have fought tooth and nail to maintain some level of contact with her?’

‘I don’t know…’ Suddenly all I can manage is to whisper through the overwhelming pain in my throat. ‘I … I don’t know. I haven’t known for years … She’s gone. I used to wonder, sometimes, if … if she ever really existed, and that maybe my brain was just playing the ultimate trick, making me imagine everything I could have been but never was. But then … then I saw Dominic’s picture. It’s from then. It’s from … it’s from a time only I would remember. And I can’t … Please, Olivia. Please don’t make me abandon her all over again.’

‘Just listen to the tape,’ Dominic interrupts, turning up the volume on my handset still quiet in front of her before anyone can say anything else. My voice crackles into the room.

‘Who are you?’

‘Perseus,’ hisses the reply, faint but clear. The face, blank as all the others, reappears in my head, the crunch of frosty leaves under my feet, the bare tree branches of St James’s Park traced across the clear sky like pencil drawings. The slap of cold air on my face, the needle-point mist of the fountain, my voice, controlled, deliberate. ‘And me?’264

‘Medusa,’ the tape says. ‘The gorgon with her eyes of stone, her crown of snakes.’

Olivia leans closer, head moving back into the light, shadow falling across her back. Fizz of static, snap of leaves as we start to move. My ribs pinch as they remember. The carpet, alien underfoot, no leaves, no grass, no mist in this glass-fronted cell. Olivia is hunched over the handset, tensed, ready to pounce, except does she know what she’s pouncing on? I mouth the words as I hear them again, ragged thrums off my collar. Papers, indiscipline, protocol. Jaqlin. Hermes. Evidence crescendos round the room until Dominic leans over to turn it off.

‘Who was that?’ She looks up at me, still hunched over her desk. I can barely see her.

‘I don’t know. I never know. They just text and I jump. I’ve always been given a password beforehand.’