Lily and her cousin, Findlay, discover that they, and their entire civilisation is enclosed  in a giant dome under the sea of another world. This world has been there for thousands of years, and no one is aware that their sky is a solid dome, deep under the sea, except for a handfull of conspiratory theorists and nutters  Orthodoxy, and science declares that talk of the “overworld” belongs to the past only.  When the ‘dome world’, which consists of 7 seperate kingdoms, comes under attack, Lily and her cousin are exposed to the truth, and in order to try and save their known world, they are forced to leave the comfort of their home and go to the over-world, a place that is supposed not to exist.