Six months since the earth-shattering events of The Space Between Us, the revelatory hope of the aliens' visit has turned to dust and the creatures have disappeared into the water off Scotland's west coast. Teenager Lennox and grieving mother Heather are being held in New Broom, a makeshift US military base, the subject of experiments, alongside the Enceladons who have been captured by the authorities. Ava, who has given birth, is awaiting the jury verdict at her trial for the murder of her husband. And MI7 agent Oscar Fellowes, who has been sidelined by the US military, is beginning to think he might be on the wrong side of history. When alien Sandy makes contact, Lennox and Heather make a plan to escape with Ava. All three of them are heading for a profound confrontation between the worst of humanity and a possible brighter future, as the stakes get higher for the alien Enceladons and the entire human race. . .