David A. Poulsen 
And Then the Sky Exploded [PDF ebook] 

2018 Red Maple Award — Shortlisted * High Plains Book Award — Shortlisted, Young Adult category When Christian learns his great-grandfather helped build the A-bombs dropped on Japan, he wants to make amends somehow.While attending the funeral of his great-grandfather, ninth-grader Christian Larkin learns that the man he loved and respected was a member of the Manhattan Project, the team that designed and created the atomic bombs dropped on Japan during the Second World War.On a school trip to Japan, Chris meets eighty-one-year-old Yuko, who was eleven when the first bomb exploded over Hiroshima, horribly injuring her. Christian is determined to do something to make up for what his great-grandfather did. But after all this time, what can one teenager really do? His friends tell him it’s a stupid idea, that there’s nothing he can do. And maybe they’re right.But maybe, just maybe they’re wrong.