Sixteen-year-old Cadence was born with the ability to cry tears of diamonds–a secret talent her parents have abused to climb the royal ranks thanks to the infinite source of wealth. At their command, she cries diamonds to pay for the pricey treatments for her sister's neuromuscular disorder. Regardless of the pain, she'll do anything for her sister, who weakens by the day.

When the prince heckles Cadence at the King's Summer Solstice Ball about her sister's disability while dancing in the ballroom, she's left on the verge of tears, threatening to expose her power. She is saved by a mysteriously charming girl who sweeps in to take the next dance—and the single diamond Cadence cried. The stranger reveals the Magi Queen sent her to tell Cadence that she's a mage, and that her power is a curse.

Yearning to discover the secrets behind her powers, Cadence sets off for the City of Magi. To claim the life she wants, Cadence must embrace her power—before she loses the bright spots in her otherwise sad existence. After all, even diamonds can shatter.