When does WondLa return?

The Search for WondLa is a children's science fiction fantasy novel by Tony DiTerlizzi published in 2010. It is the first book of the WondLa series. Eva Nine has lived her whole life in an underground Sanctuary. She is desperate to find someone else who is like her, and a single clue gives her hope. In the epilogue, a human boy named Hailey swoops down from the sky to take her home.