Good Night World

On the eve of mankind's collective emigration to a new planet, the last engineer left behind initiated the global lights-out procedure. When all the cities went dark, he unexpectedly received a signal from a deep-sea detector - it was the first time that a group of humpback whales sang a good night song composed by humans. It turns out that the melody he secretly implanted twenty years ago has been passed down from generation to generation in whale songs, becoming the earth's last gentle farewell to civilization.