I'm currently following this manga. Awesome manga by the way. It's about people dying in their sleep. This is caused by a monster called Bouma.
Accumulated desires and evil thoughts naturally evolve into a life form called Boumas. These Boumas are ranked according to their colour, white being the weakest. I can't remember properly, but if I'm not wrong, either red or blue is the strongest. They go up in rank (colour) when they consume human souls. The more they consume, the stronger and smarter they become.
The main characters so far are Yume, Muca and Ken.
Yume is your everyday average girl with average grades. Her friends and her found a cat with a dandelion-like tail at a void deck. This cat is called Muca. Somehow, Yume ends up taking Muca home, where she encounters her 1st Bouma in her dream. Muca shows up, saves her and teaches her how to Dreamwalk, the art of moving around in dreams destroying Boumas.
Muca is one of 5 generals in the dream world. His codename given to him by the Boumas is Night Lynx. Fitting eh? Muca shows up to save Yume, giving her weapons in the process: a pair of gloves which generates a weapon and a pair of boots to enhance her mobility in the dream world.
Ken is the genius of the class. Stuff happens and he finds himself in the dream world together with Yume. More stuff happens and a black Bouma appears. Yume gets whacked around by it and Ken steps in to save the day, even though he has no prior training. He transforms his bracelet into a weapon and destroys the black Bouma effortlessly.
Nearing the end of the manga, a new enemy appears. She is a little girl called Belle and she is causing nightmares to children.
This is the end of vol1.
In vol2, Belle makes a full appearance and lotsa stuff happens. Ken gets kicked around a lot by giant puppets in this issue... When Yume and Ken are defeated, Belle says it's all thanks to her big brother. Muca steps in and suggests to play a game to end all this. His conditions are that the moment Yume and Ken disrupt her waves, she loses and has to tell him about this big brother of hers. Belle agrees and adds a condition of her own: Muca cannot help.
Read the rest by yourself ;P