I'll Stop the World - Lauren Thoman - Bog

Trapped in a dead-end town, Justin Warren has had his life defined by the suspicious deaths of his grandparents. The unsolved crime happened long before Justin was born, but the ripple effects are still felt after thirty-eight years. In a cosmic twist of fate, Justin's choices send him crashing into the path of determined optimist Rose Yin. Justin and Rose live in the same town and attend the same school, but have never met-- because Rose lives in 1985. Justin won't be born for another twenty years. And his grandparents are still alive. Justin and Rose have a week to get Justin unstuck in time and put each of them in control of their futures--by solving a murder that hasn't happened yet.--Adapted from jacket