The book is Graham’s Charlotte by Drew Farnsworth. It was the winner of Columbus Creative Cooperative’s Great Novel Contest in 2013.
The plot centers around angsty teenager Madison Riley. Madison acquires an all-knowing cell phone and has to use it to save her mother from impending danger. I won’t spoil the rest.
A lot of recent YA bestsellers are marketed to teenagers, but they actually target adults. I think Farnsworth can be praised for not trying to play both sides of the market. He knows his audience and he doesn’t stray from what will work best for them.
This probably shouldn’t be your first choice if you’ve already graduated high school, but it should appeal to the young adults it was written to entertain.