The Queen of Springtime - Robert Silverberg

Nebula Award–winning author: Humans have emerged to reclaim the Earth after the Long Winter. But they never anticipated the battle that awaits . . .

As Earth thaws after the Long Winter, the remaining human tribes journey from beneath the continent to the fertile land above. But the hjjk, an ancient insectlike race that remained on Earth's surface throughout the frozen eons, stand in their way. Keeping a tight grip on their power, the hjjks are the chief barrier to the people's further expansion in the New Springtime. When Kundalimon, a human who has lived with the hjjk for seventeen years, arrives as an emissary of peace, the tribes are wary. They rely on Nialli Apuilana, who had been stolen at thirteen by the hjjk and released months later, to ascertain his true mission. But in this new world, it's hard to know whom to trust. As both sides prepare for war, the fate of the planet hangs in the balance.

The Queen of Springtime is the second book of the New Springtime series, which begins with At Winter's End.