Terminally ill youth Qin Yi binds with a system, editing videos of history's top ten regrets, broadcasting them across time and space via the heavenly canopy. Extending his life depends on making up for these regrets. From the An Lushan Rebellion and Zhuge Liang's death from illness, to Xiang Yu at Wujiang, Yue Fei's wrongful execution, and the downfall of the Qin Dynasty, every single case strikes straight at the heart. Emperors and famous generals such as Ying Zheng, Liu Bang, Li Shimin, and Zhu Yuanzhang watch the heavenly canopy together, feeling shocked, remorseful, or enlightened. In parallel universes, can regrets be rewritten, and where will history head toward unknown horizons?