IT'S EASY to imagine Julia Gfrörer drawing her new book, Black Is the Color, while hunched over a sketchbook in the darkest corner of the creakiest, dustiest coffee shop she could find—possibly wearing some sort of cloak. "Her name rhymes with despair," her author bio tells us. "Her heart is black as jet."

And Black Is the Color is a dark tale indeed: With only a corpse for company, a young sailor is cut loose by his captain and cast adrift to die. He is soon visited by an alluring, mysterious mermaid, whose comforts are questionable at best.

But the mermaid is part of an undersea posse of merfolk who gossip, play in bands, and hang around shipwrecks waiting for drowned sailors to play with. ("These young guys probably wouldn't even know where to put it," scoffs one mermaid of a new crop, as a ship sinks in front of them.) Their humor balances out the doom 'n' gloom of Gfrörer's obsessively detailed ocean waves, her vast, blacker-than-black night sky. Here, light and darkness live side-by-side; the life-and-death stakes of one realm hardly register in the other. Black Is the Color isn't all about despair—it's more interesting than that.