Pariyerum Perumal narrates the story of a youth hailing from Puliyankulam village near Tirunelveli. Pariyan (Kathir) belongs to an oppressed caste. The movie begins with the brutal murder of his beloved black dog ‘Karuppi’ (Lit. Blackie in Tamil). The canine hunting companion of Pariyan is the first one we see becoming a victim of caste hegemony.
Pariyan moves on to secure a seat in a law college, where he wishes to become a lawyer like B. R. Ambedkar. He meets Jothi Mahalakshmi alias Jo (Anandhi), a naive girl from Ambasamudram who takes it upon herself to teach English to Pariyan. She eventually falls for his innocence and honesty. This newfound friendship irks Sankaralingam (Lingesh), a fellow law student and Jo’s cousin. He awaits a chance to teach a lesson to Pariyan and establish his caste superiority. He does so while the blissfully unaware Jo invites Pariyan to a family wedding.