Gliding over the top deck beside Harry, she was careful to use her fins as little as possible so as not to kick up silt and reduce visibility. He headed towards the bow. The wooden decking had long gone, but the iron framework remained in place like a giant waffle iron covered in a multitude of crustaceans that made the ship’s skeleton a classic wreck reef, teeming with wildlife.

She aimed her lamp through the structure, to the lower deck. The light bleached away colour at the centre of the beam, changing the pink icing-sugar formations into delicate antique lace. She longed to venture inside and turned to look for Harry. He investigated an enormous cannon that seemed perfectly preserved on the foredeck. She was tempted to venture inside the ship alone, but common sense stopped her. Somehow Shelly knew she would come again.

Harry turned, peered through his mask, searching for her, his lamp shining through the fishnet, her headlamp catching his face, blinding him. She caught his squint, the spotlight giving his face a ghoulish appearance. In one horrendous moment, her twenty-year-old nightmare returned with stark reality. Her scream, dulled by the rubber of her breathing tube, was hardly audible to Harry, yet it exploded in her chest as the past roared up before her.

Suddenly, she was sixteen again. She’d never snorkelled before. The young man she adored was teaching her . . . but things went wrong, so terribly wrong.

‘My mother’s bracelet,’ she had pleaded. ‘Please, please, try and find it. Dad will go crazy if I lose it.’

Then she was floating on her back, shaking, screaming, screaming, ‘Help! Help me!’

An age before anyone reached her. Splashes as men jumped into the sea. Shouting. People pulling her away. Ambulance sirens. The smell of bleach. Doctors, nurses, policewomen, foreign language, forms. Newspapermen with their cameras. Look this way! Flash! Medication that made her drowsy, numb. Days of battling with a fogged mind, tears, questions. Asking for forgiveness. Her father’s arrival in Greece, his anger because she’d lied to him about a school trip. Going home to England. Her father furious, impossible to talk to.

She felt the shaking of her shoulder and in an instant, she was back in the present with Harry beside her, his eyes questioning. He held out a hand, wiggled and tilted it from side to side, asking if something was wrong. Shelly shook her head, then nodded, made the OK sign, and realised she was holding her breath. She made a conscious effort to calm herself and concentrate on her breathing.

God, oh, God! Would it ever go away? The past . . . the nightmare.