In the quiet of the lab, surrounded by the hum of machinery and the soft glow of computer screens, Kai and Dr. Nair worked with a fervor driven by the ticking clock of the prophecy. The decoded song, now a complex symphony of digital notes, was the key to unlocking the ocean's revival.

The biologist's hands were a blur, his eyes alight with the fire of discovery as he mapped the song's intricate patterns. It was a puzzle of frequencies and rhythms, a code that, once cracked, would resonate across the seas and speak to the very essence of life within.

Kai, with the memory keepers' stone clasped tightly in his grasp, felt its pulse synchronize with the decoded notes, a harmony that bridged the gap between science and the mystical. It was as if the stone was coming to life, its purpose entwined with the song's destiny.

Together, they pieced together the melody, a tapestry of sound that held the promise of a new beginning. The song was more than a call to the creatures of the deep; it was a plea to humanity, a directive encoded in the language of the sea.

As the final notes fell into place, the lab was filled with the song's power, a sound that seemed to transcend the barriers of the physical world. It was a call to action, a beacon of hope that needed to be heard by all.

The task ahead was daunting. They needed to broadcast the song far and wide, to reach the ears of those who had turned a deaf ear to the ocean's plight. It required a network of underwater speakers, a technological feat that stretched the limits of their resources.

But the song's message was clear, and its urgency undeniable. It spoke of balance, of the interconnectedness of all life, and of the role humanity must play in restoring the health of the oceans.

With the decoded song in hand, Kai and Dr. Nair prepared to take their next steps. They would reach out to the world, to anyone who would listen, and share the song that could change the fate of the seas.

The ocean's whispers had become a roar, a symphony of hope that would not be silenced. Kai and Dr. Nair were ready to amplify its call, to awaken the world to the beauty and the necessity of the ocean's song.