By the last page, both mother and daughter can open the Obelisk Gate — and they want opposite things with it. Essun, carrying on Alabaster's plan, means to catch the Moon and restore it, to end the Seasons and, she hopes, save the world and her daughter. Nassun, guided by Steel toward nihilism, means to bring the Moon down and end everything. They're on a collision course, each learning the Gate independently, separated by half a planet. It's a devastating inversion of the reunion Essun has walked across a dying continent to earn: she's spent two books trying to reach a daughter who may become her enemy.
Hoa's interludes also gesture at a much older story — an ancient civilization, a war humanity started, the origin of stone eaters — that the final book, The Stone Sky, will unfold in full.