The Riddles of Epsilon

I had spotted this book a while back at the bookstore but had to wait several months for it to enter into the library's system: The Riddles of Epsilon pits its disgruntled teenage protagonist against powerful forces and those that follow them. Jessica is stuck w/ her parents at a family house for the summer when a supernatural being named Epsilon contacts her online and in the real world to gain her aid in an ancient battle of good vs. evil. The "riddles" and light codebreaking does give the story some mystery but I didn't care for the 1st person tone used. This was an okay read, although I did finish most of it in 1 sitting.