Oro leads Isla out across the dark Mainland without explanation. Isla, tired of his contempt and silence, stops and demands that Oro treat her as a fellow ruler. Oro finally says they are going to “the storm,” and Isla follows Oro toward the coast.

They reach the frozen cursed storm: suspended lightning, fire, water, and a towering wave revealing treasures on the seafloor. To get closer, Oro expects Isla to cross dangerous cliff bridges, but Isla refuses unless Oro stays beside her. Their argument reveals that Oro did save Isla after her earlier fall by healing Isla’s head injury, though Isla still resents being abandoned afterward.

At a rocky outcrop near the storm, Oro tells Isla to jump into a dark vertical shaft after him. Isla suspects this may be a trap or a test, but Isla chooses to jump because finding the bondbreaker and gaining access to the Sun Isle library still depend on Oro. Isla lands in freezing water below, and when Oro pulls Isla out, Isla realizes Oro has tested whether Isla can trust him.

After Isla confronts Oro, Oro admits the trust test and asks whether Isla will share what Oro tells Isla with Grim. Isla says no, and Oro reveals he is searching for Lightlark’s heart, the island’s true source of power and life-force. Oro explains that Oro is only a conduit: if the power is unbalanced or cannot be channeled, Lightlark will crumble.

Isla discovers they are inside a hidden Wildling-built garden in the mountain, containing plants from every isle. Oro needs Isla’s knowledge because Lightlark’s heart blooms every hundred years attached to a living plant. Isla studies the garden and identifies likely hosts: plants that can carry hidden things, trees that can shield or imprison living beings, and rooted water lilies.

With Isla’s guidance, Oro says Oro will choose a place to begin searching. Because there is no easy exit and sunrise approaches, Oro carries Isla and flies out through the shaft, terrifying Isla with the height and an invisible aerial path back to the Mainland. Oro leaves Isla to walk home alone, promising to see Isla the next day in a tone that sounds more like a threat.