Five years before actor-producer Kagiso Modupe’s father died at the age of 70, the elderly man visited the grave of his own dad for the first time. There, he broke down and cried over his deadbeat father, who had abandoned him when he was a young boy to start another family.

Modupe, who was with his father at the grave, describes the visit as the most heart-wrenching thing he’s ever seen. But that memory planted a seed for the equally heartbreaking thriller in which Modupe, 36, and his nine-year-old daughter now star...