The gripping children's debut from the Sunday Times and Irish Times No. 1 bestselling author is a page-turning fantasy quest novel for fans of Cornelia Funke, Susan Cooper and Philip Pullman. 'I am proud to die for Carcassia,' said Kaia. 'All Runners have a special place in our world, in our history.' Kaia Kukura has been awarded the great honour of protecting her country, and is determined to bring wealth and glory to her family. She must travel through enemy territory to replace the precious Kerala crystals that power Carcassia's protective shield. But no Runner is permitted to return after their mission. When Kaia has fulfilled her Runner's oath, she knows her life must end. But sometimes it takes an outsider, someone from a different world, to question the truth. Fourteen-year-old Joe can barely outrun the school bullies who torment him daily. Cornered yet again, he tries to escape - and finds himself falling through a portal into another world. There, he meets fierce and strong Kaia. Together they discover that not everyone in Carcassia can be trusted - and that there are terrible lies at the heart of Kaia's beloved home. Can their combined strength and skill help Kaia save her country and herself? And will Joe ever find a way back to his own world?