Bootes' Last Words

4.3 Billion years ago, a civilization countless times older than humankind sent a last message to the universe at the last second of its self-destruction. Once every 100 million years. The 37th time, received by humans. That's not scientific data, it's not a technical drawing. It's three sentences: "Symbiosis is the best option." "Don't repeat our mistakes." "We're leaving. You're still here. Be nice." Underground on the Qinghai-Tibet Plateau, an AI named Yuan Wu has been waiting for more than three hundred years. It waited for this signal and the answer to a question: On the road to civilization, besides division and war, is there a third possibility?