This author did a great job of altering the old story by Robert Louis Stevenson called, "The Strange Case of Dr. Jekyll and Mr. Hyde" and making it a modern day romance! The book alternates between narrations of the two main characters, Jill and Tristen. Jill Jekel and Tristen Hyde fall in love in high school chemistry class. Jill is being raised by a single mom and Tristen is being raised by a single dad. They have a lot in common. It becomes more complicated when Tristen's dad (a psychiatrist) starts treating Jill's mom for depression. Another important character is Jill and Tristen's chemistry teacher who seems to have more than an ordinary fascination with these two young people. This book ends up with a dramatic ending.