Strangers in Time by David Baldacci

From the #1 New York Times bestselling author of A Calamity of Souls comes David Baldacci’s newest novel, set in London in 1944, about a bereaved book shop owner and two teenagers scarred by the Second World War, and the healing and hope they find in one another.
Fourteen-year-old Charlie Matters is up to no good, but for a very good reason. Without parents, peerage, or merit, he steals what he needs, living day-to-day until he’s old enough to enlist to fight the Germans. After barely surviving the Blitz, Charlie knows there’s no telling when a falling bomb might end his life.
Fifteen-year-old Molly Wakefield has just returned to a nearly unrecognizable London. One of millions of children to have been evacuated to the countryside Molly has been away from her home for nearly five years. Her return, however, is not the homecoming she’d hoped for as she’s confronted by a devastating reality: neither of her parents are there.
Without guardians and stability, Charlie and Molly find an unexpected ally and protector in Ignatius Oliver, and solace at his book shop, The Book Keep. Mourning the recent loss of his wife, Ignatius forms a kinship with both children, and in each other they rediscover the spirit of family each has lost.
But Charlie’s escapades in the city have not gone unnoticed, and someone’s been following Molly since she returned to London. And Ignatius is harboring his own secrets, which could have terrible consequences for all of them.
As bombs continue to bear down on the city, Charlie, Molly, and Ignatius learn that while the perils of war rage on, their coming together and trusting one another may be the only way for them to survive.