Destroy all monsters
(Book)

Ash does not remember the day she fell out of her friend Solomon's tree house, but ever since that day Solomon has retreated into a dark fantasy world and Ash believes the key to saving him is recovering her lost memory.

"Solomon and Ash both experienced a traumatic event when they were twelve. Ash lost all memory of that event when she fell from Solomon's treehouse. Since then, Solomon has retreated further and further into a world he seems to have created in his own mind. One that insulates him from reality, but crawls with foes and monsters . . . in both animal and human form. As Solomon slips further into the place he calls Darkside, Ash realizes her only chance to free her best friend from his pain is to recall exactly what happened that day in his backyard and face the truth--together.", --Amazon.