Dayoung is part of the New York Teen Police Department "NYTPD", when she learns that her present "2013" should never have existed, that someone went back in time to 1986 and changed the past to create the future she now knows, she goes back in time to set things right.
Dayoung's 2013 is like a dream, they have flying cars, rocket packs, the works; the only problem is, that future should never have existed. If anyone remember Back to the Future II, where the Doc tell Marty that the 1985 they've returned to is a tangent of the created and some point in the past; well that's Dayoung's 2013, a tangent created in 1986 when someone went back in time to alter things.
In 1986 New York is crap, especially when you compare it to the New York of 2013 in the book; so Dayoung has a lot of adjusting to do.
Although the concept has been done before, time-travel is still very good, as the possibilities are infinite. I look forward to reading the continuation of Dayoung's adventures in restoring the timeline.
Rating 4 out of 5