One of my favorite scenes in "The Angel's Game" by Carlos Ruiz Zafón is when David finally finds Cristina wandering aimlessly on the frozen lake:

...

I followed the tracks as far as the park that bordered the lake. A full moon burned over the large sheet of ice. That is when I saw her. She was limping over the frozen lake, a line of bloodstained footprints behind her, the nightdress covering her body trembling in the breeze. By the time I reached the shore, Cristina had walked about thirty metres towards the centre of the lake. I shouted her name and she stopped. Slowly she turned and I saw her smile as a cobweb of cracks began to weave itself beneath her feet. I jumped onto the ice, feeling the frozen surface buckle, and ran towards her. Cristina stood still looking at me. The cracks under her feet were expanding into a mesh of black veins. The ice was giving away and I fell flat on my face.

"I love you," I heard her say.

I crawled towards her, but the web of cracks was growing and now encircled her. Barely a few metres separated us when I heard the ice finally break. Black jaws snapped open and swallowed her up in a pool of tar. As soon as she disappeared under the surface, the plates of ice began to join up, sealing the opening through which Cristina had plunged.

...

There's more and it gets better and better, but I don't want to spoil it all for those who want to read this fantastic novel.

This is just one of many gripping parts of the book which takes place in the old, shadowy sections of Barcelona and surroundings. The story is an excellent read, although you will probably want to reread certain sections in order to get the most out of the darker and more mysterious chapters, trying to figure what's real and what's coming from the author's fantastical mind.