The Light Between Worlds by Weymouth, Laura E.

Six years ago, Evelyn and Philippa Hapwell cowered from air strikes in a London bomb shelter. But that night took a turn when the sisters were swept away to a strange and beautiful kingdom called the Woodlands, where they lived for years in a forest straight out of myth and legend.

When they finally returned to London, no time had passed and nothing had changed - nothing, except themselves. Now Evelyn is desperate to return to the Woodlands no matter what it takes, while Philippa just wants to move on.

But when Ev goes missing, Philippa must confront the depth of her sister's despair. As the weeks unfold, Philippa wonders if Ev truly did find a way home . . . or if the weight of their worlds finally pulled her under.