Forgotten from Astraloon

Imagine a megapolis where airships fly alongside flying carpets, people walk the streets in pajamas, and engineers can summon rain with a snap of their fingers.
In such a strange city lives Holly Nightingale — a simple employee of the National Museum, whose life turns upside down when her younger sister Clara goes missing. But things become even stranger when the girl discovers that no one remembers Clara...
Holly has to untangle a web of lies that turns out to be more than she could ever imagine. Who is behind the mysterious disappearances? And how are they connected to the founding of the city?