Ma Ke has been diagnosed with Alzheimer’s disease. That a tough pill to swallow for anyone, but Ma Ke was once the Artistic Director of the Shanghai Opera Theater. His mind was sharp, and if an actor forgot their line, Ma Ke didn’t. Over 80 shows, he would tell anyone who would listen: The most prolific director of his time.

But now, all those memories will be lost in time like tears in rain. Faced with a crushing reality, Ma Ke’s son, Chinese conceptual artist Maleonn, has an answer: Put on a show. A theater project called “Papa’s Time Machine,” about a son traveling back in time to find his father’s lost memory.

“Papa’s Time Machine” is Maleonn’s first theater project, and it’s an ambitious one. The characters are puppets resembling steampunk automatons. It’s a nod to H.G. Wells’ seminal novel, ditto for the shows’ décor. But where Wells had Morlocks to mess things up, Maleonn’s foes are the clock and the constantly dwindling supply of fund. Directors Yang Sun and S. Leo Chiang follow Maleonn from concept to completion in Our Time Machine. The change from “Papa’s” to Ours is a nice touch as the movie starts with Maleonn still a bachelor. His approach to “Papa’s Time Machine” is as a son. By the movie’s end, he will become a father, and will no doubt see his project from a different perspective. It’s a sweet doc, one that neither over-extends itself nor gins up daily conflicts into climactic moments.

Our Time Machine broadcasts on Sept. 28 on PBS’ documentary series POV.