The Portal — Brock E. Deskins

Life is worse than boring for Dour Drew, as his friends call him. Disillusioned by reality and tired of being a “bully magnet,” Drew plans an epic night of fantasy role playing with his friends, a night where they can leave the mundane world behind and become heroes. But when Drew buys an old spell book from a local bookstore to add some special ambience to his game night, he accidentally destroys the line between fantasy and reality.
The magical portal Drew opens sucks him into an alternate world, one where magic and monsters are all too real. Now it's up to his nerdy friends to and big brother to rescue him. What Drew's captors don't know is that it might be they who needs rescuing from Drew.