I’ve been a fan of Francis Hardinge’s wonderful, morally complex novels for young adults since reading The Lie Tree, which won a Costa Book Award for Children’s Book (best novel by an author residing in the UK or Ireland) in 2015. Her novels have consistently brought a teen protagonist through an adventure which requires obtaining, not increased physical or mental prowess, but the maturity to make a difficult decision.

The young protagonist of Deeplight, Hark, is an orphan who has grown up (at age 15) to be a thief and con man, dealing in magical relics. He starts out as the typical street-kid-with-a-heart, but becomes much more interesting. He is joined eventually by Selphin, a young woman whose mother is a pirate, who also has unexpected steel in her moral fiber. She is, interestingly, “sea-kissed,” which means she has lost her hearing during undersea diving. There is a community of “sea-kissed” and most of Selphin’s conversations in the book take place in sign language.

Hardinge’s books all have unique fantasy worlds with interesting magic operating under unusual conditions. Deeplight is no exception. Its world is called Myriad, a huge chain of islands which had, until fifty years ago, been ruled by vast, Lovecraftian undersea Gods. They have left behind relics with incredible power, an economy which centers on harvesting those relics, and an abandoned priesthood aging on a deserted island.

And Gods also, of course, leave behind secrets for unsuspecting teenage protagonists to discover. The secrets of Myriad are layered and complicated, but well within the understanding of the people like Hark and Selphin, who can grow to treasure them.