IRIDESCENCE.
I read that word in one of Atticus's thick old books once. When I went to Jack to ask what it meant, he held his hands out and they glowed so gentle I thought they might kiss the air, and since that day I wanted a place that was iridescent, that lit without burning. Being in love is sort of like that, when it's real. When it's true.

Matthew has loved Ariel from the moment he found her in the tunnels, her blond hair shining and her bee’s wings falling away. They live in Safe, an underground refuge for those fleeing the city Above--as does Whisper, who speaks to ghosts, and Jack Flash, who can shoot lightning from his fingers.

But one terrifying night, an old enemy invades Safe with an army of shadows and only Matthew, Ariel, and a few friends escape Above. Forced to survive in the most dangerous place he can imagine, Matthew strives to unravel the mystery of the shadows' powers and Safe's own secret history. For he knows he must find a way to remake Safe--not just for himself and his friends, but for Ariel, who's again faced with a life she fled, and who needs him more than ever before.