The City of Dreams and Nightmares

(Basically a Horror/fantasy book :3)The main character, Lilith, was always told of stories of the made-up city. Only the people of pure heart had no nightmares and only dreams. It was told that if you were pure of heart, you could go into that city and all your dreams would come true. It was also told to never walk into the city alone and NEVER stay around for the nighttime, especially if you are not pure. Lilith has a lot of dreams. Mostly nightmares. She dreams of getting rid of these nightmares, and what other place would be good other than the City of Dreams and Nightmares? I mean, what could possibly go wrong? (P.S. IT'S MATURE BECAUSE OF GORE)