The battle for the Sunken City had left its mark on both sides. The once impenetrable dome, a symbol of isolation and secrecy, now lay fractured, a testament to the determination of the surface survivors. Kai stood amidst the ruins, the weight of leadership heavy upon his shoulders.

The city's inhabitants, stripped of their arrogance, faced the survivors with a mixture of fear and awe. They had never imagined the surface dwellers capable of such defiance, such strength. The confrontation was not just a clash of arms but of ideologies.

Kai addressed the gathered crowd, his voice echoing through the damaged corridors. "We stand at a crossroads," he began. "The tide has risen, and it has brought change. We can continue to fight, to let the waters claim us all, or we can unite and rise above the tide together."

The city's leader, humbled by the uprising, stepped forward. "We have technology that can help control the waters, to give us all a chance," they offered, extending a hand in peace.

The survivors, weary of battle but hungry for hope, listened. Among them were engineers, scientists, and leaders who had kept the flame of knowledge alive against all odds. They stepped forward, joining Kai and the city's leader.

Together, they devised a plan. The city's advanced technology, combined with the surface's ingenuity, could strengthen the weakened dome, turn back the rising seas, and reclaim the land that had been lost. It was a monumental task, one that would require the efforts of every willing hand.

The agreement was a fragile thing, born of necessity and the shared desire to survive. The Sunken City would no longer be a refuge for the few but a beacon of hope for the many.

As the repairs began, a sense of purpose united the two peoples. The city's glow, once a symbol of division, now shone as a sign of cooperation. The surface survivors brought their knowledge of sustainable living, teaching the city's inhabitants how to coexist with the environment rather than dominate it.

Kai watched as the two worlds came together, the beginnings of a symbiotic future taking shape. The path ahead was fraught with challenges, but for the first time in a long while, there was hope.

The novella ends not with the closing of a chapter but with the opening of a new one. The Sunken City, once lost beneath the waves, now stood as a testament to the resilience of the human spirit and the unyielding power of unity.