Korrien Moontouched is the Heir of Light. As if the pressures of helping his mother and Queen lead their growing clan weren't enough, he and his twin sister have grown up knowing they are the keys to the Devourer's final defeat—to concluding the Battle for Earth, which has been frozen in time since before he was born.

When Earth's time thaw begins, Rien is thrown into the Seven Realms' efforts to secretly protect humanity from their common enemy. The thaw also offers Rien his only chance to find his consort—because Rien has to marry a pure human of Ice.

But the only Earthren to have escaped the time freeze is nothing like what the logical, perfectionist prince had so carefully planned for himself. As feisty and unpredictable as she is pretty and petite, Sierra Knight encapsulates everything Rien finds aggravating . . . and irresistible.

Serona Sunfilled is the Heir of Flame. Even so, the bubbling young woman has only three goals in life: One, keep her twin brother sane. Two, make her papa and King proud. And three, find the mate the Tree of Flame promised her and live happily ever after.

Yet things aren't quite that simple. When the Tree of Flame sends Rona to an unknown world, the dragon who awaits her is nothing like she had expected—and belongs to the rarest of Powers, one that can only be born from the embers of calamity.

Suddenly, nothing is as perfect as the sunny princess believed it would be. Though Drevior is as tantalizingly handsome as he is scarred, he returns with her carrying secrets and sorrows—and he brings a dire warning of an entirely new threat to the Seven Realms . . . which he will risk everything, even his life, to deliver.

For there are other dark powers besides the Devourer, and as the Devourer weakens and its defeat approaches, one of them turns its thirst on the Seven Realms. If the Realms and Earth are to survive, both Rien and Rona will have unite all four Powers of Life—Flame, Ice, Light, and Ember . . . in one.