In Search of Lost Time (Chinese: 海的尽头是草原) is a 2022 Chinese historical drama film co-written and directed by Derek Yee and starring Chen Baoguo, Ma Su, Ayanga, and Wang Qiang. Based on real events of "Three Thousand Orphans Entering Inner Mongolia", the film is about a group of nearly 3,000 junior orphans who were sent to the Mongolian grasslands to be adopted by nomadic families. The film premiered in China on 9 September 2022.