The World at Midnight

From #1 New York Times bestselling Sisterhood of the Traveling Pants author Ann Brashares and her brother Ben Brashares comes the third and final book in the action-packed middle grade alternate history thriller trilogy that asks what present-day America would be like if Germany had won World War II.
Henry, Frances, and Lukas are still stuck in Westfallen in 2023. They're out of ideas on how to get home until they discover a series of historical comic books that outline how Nazi high command in Germany found out the details of D-Day. Now they've got to work with their friends Alice, Lawrence, and Artie in 1944 to follow the clues in the comic books to stop the message from getting across the Atlantic.
Lukas has been conscripted to play baseball—normally impossible for a Jewish kid in Westfallen, but his talent is undeniable—and he's got to find a way to stay on the team and stay alive when everyone around him wants to see him fail or worse. That gets tougher when a scrappy Jewish orphan and runaway starts following him and hiding under his bed.
Meanwhile, in 1944, Artie finds out his German-born father is more involved in helping the Nazi cause than he realized—and when his father steals the radio that allows them to talk with kids across time, everything they've worked for is threatened. And once Henry discovers there's way more to the mysterious well than any of them ever imagined, it's going to take all six kids' courage, ingenuity, and a bit of luck to swim against the tide of time and restore the future.