Ordinary office worker Cheng Xiaoyang unexpectedly acquires an antique pocket watch that can stop time, only to discover that each use comes at a terrifying cost: nosebleeds, temporary blindness, and even accelerated aging. While investigating, he meets the mysterious Su Yuqing, who carries a bronze mirror that can foresee the future. Together, they discover that all the time-altering artifacts come from a shattered time dimension, and that a mysterious organization called Sands of Time is forcing their users to spend their lifespans to open the Great Moment, a gateway to parallel worlds.
When Cheng Xiaoyang's younger sister, Cheng Xiaoyu, is in a car accident, he is forced to activate the pocket watch's golden hand and speed up time to save her. The price is that his right hand ages twenty years in an instant. Meanwhile, Su Yuqing's identity is exposed: she is actually Cheng Xiaoyu from another timeline, who came back to prevent the world from collapsing. In the end, Cheng Xiaoyang faces a wrenching choice: save the sister before him, or help Su Yuqing destroy all the time-altering artifacts and end the cycle? And the pocket watch's final silver hand holds the ultimate power to reverse everything... or destroy it all.
