"Joy must uncover a deadly conspiracy at the heart of Apex City--and lead her fellow Hunters to victory in the final confrontation with the dangerous Othersiders"--

When Ellie Baum accidentally time-travels via red balloon to 1988 East Berlin, she's caught up in a conspiracy of history and magic. She meets members of an underground guild in East Berlin who use balloons and magic to help people escape over the Wall. But even to the balloon makers Ellie's time travel is a mystery. When it becomes clear that someone is using dark magic to change history, Ellie must risk everything-- including her only way home--...