The analogue clock on her nightstand told me it was just after 3 in the morning.

I was only about three pages in to The Tell-Tale Heart when I noticed Bella's own heart ratchet up in pace, a sure sign a screaming nightmare was worming its way into her dreamscape.

While we did not verbally discuss the horrifying scenarios that plagued her at night, it was not difficult to guess - more often than not, her agonized shrieks were contorted around my name, begging me not to leave. Every time was a silver stake through my soul.

It was our nightly ritual, as I was unable to stay near her too long when she was so rail-thin, my vanished presence always precipitating the nightmare.

I knew, because one night I had wrapped her in several blankets and lain next to her all through the night. Her lips had been blue the next morning despite the precautions, but she had slept still and without trauma.

She could live through a nightmare, even though it killed me. She could not live through hypothermia.

On queue Bella jerked upright in bed, sallow brunette locks flying, a sustained scream on her lips.