It sounds like you're referring to a specific film, short story, or folk tale titled Mother-in-Law Who Opens Up When the Moon Rises from 2021.
The request appears to reference the 2021 South Korean historical drama " River Where the Moon Rises mother in law who opens up when the moon rises 2021
By 7 PM, my mother-in-law was a shadow in the kitchen—silent, judging my every chop of an onion. But at 8:47 PM, as the November moon slid past the balcony railing, she sat beside me on the floor.
“When I was seventeen,” she whispered, “I buried a box under that same moon.”
For the first time in three years, she smiled. It sounds like you're referring to a specific
So although not opening ' when moon rises mother ' but check . “When I was seventeen,” she whispered, “I buried
The title "Mother-in-law who opens up when the moon rises" appears to be