A fantastical novel, a wildly inventive tale—by turns poignant and funny, lusty and wrenching—about love and heartbreak. Edinburgh, 1874: Born with a frozen heart, Jack is nearly dead when his mother abandons him to the care of Dr. Madeleine—witch doctor, midwife, protector of orphans—who saves Jack by placing a cuckoo clock in his chest. It is in her orphanage that Jack grows up, amid tear-filled flasks, eggs containing memories, a man with a musical spine.

As Jack gets older, Dr. Madeleine warns him that his heart is too fragile for strong emotions: he must never, ever fall in love. And, of course, he does: on his 10th birthday and with head-over-heels abandon. The object of his ardor is Miss Acacia—a bespectacled young street performer with a soul-stirring voice. But it’s not only Jack’s heart that’s at risk, it’s his very life—and doubly so when he injures the school bully in a fight for the affections of the beautiful singer. Now begins a wild journey, of escape and pursuit, from Edinburgh to Paris to Miss Acacia’s home in Andalusia, where Jack will finally learn the great joys, and ultimately the greater costs, of owning a fully formed heart.