In this gripping finale to Christelle Dabos's international best-selling Mirror Visitor saga, Ophelia, the mirror-traveling heroine, and Thorn discover that the truth they have been seeking has always been hidden behind the mirror.

Christelle Dabos takes us on a journey to the heart of a great game to which the all-too-human affairs of her book's protagonists are ominously connected.

The distrust between them has been overcome and now Ophelia and Thorn love each other passionately. However, they must keep their love hidden. Only in this way can they continue their journeys toward an understanding of the indecipherable code of God and the truth behind the mysterious figure of the Other, whose devastating power continues to bring down entire pieces of arks, plunging thousands of innocents into the void.

Ophelia and Thorn arrive at the observatory of the Deviations, an institute shrouded in absolute secrecy and overseen by a sect of mystical scientists who secretly conduct terrifying experiments. There, Ophelia and Thorn hope to discover truths that will halt the destruction and death and bring the world back into balance.