If Malai portrays Phapo as a father to Sangmong, his wife, Yupphadi, is consequently positioned as the young man's mother.
Phapo may be Sangmong's uncle rather than father and Yupphadi his aunt by marriage rather than mother, but in its details Chua fa din salai actually represents the three characters as a nuclear family.
The young man begins a torrid love affair with his mother figure that lasts for about a year before the two are, one day, caught red-handed by Phapo himself.