The fourth season of Ang Probinsyano, a Philippine action drama television series, premiered on ABS-CBN's Primetime Bida evening block and worldwide on The Filipino Channel.

With the remaining members of Pulang Araw and his allies in prison, Cardo forms the vigilante and revolutionary far-left group Vendetta to combat corruption, injustice, oppression, and despotism in the Philippines.

Cardo and the rest of the Pulang Araw move to Manila with the help of Engelbert "Bert" Moreno, alias "Daga" (Rico J. Puno) (transl.

Bert's daughter, Regine (Angeline Quinto), resents Cardo as she recognizes the latter as the CIDG officer who killed her brother Banjo (Eric Fructuoso).

In order to make Renato Hipolito pay for his brutalities and the betrayal of his formerly associated group, Pulang Araw, Romulo, Cardo, and Anton attempt to investigate his past and unmask the real motive behind the mass bombing incidents in Manila.

De Silva subsequently joins the hunt for Pulang Araw to catch up to Hipolito in the ratings, both eyeing the top spot to secure the nomination for the Senate of the Philippines.

His family is rescued by Pulang Araw and finally discovers Senator De Silva's involvement in the assault on Bert's family,the following day Bert is given a simple funeral and buried the next day his death was finally avenged when Cardo and Romulo's group overpower and execute De Silva's lackeys.Regine and her brother Bruno (Janno Gibbs) move in with Pulang Araw.

After visiting his dead son's grave, Don Emilio and his henchmen kidnap and torture Cardo on an isolated island called Isla Muerte (transl.

In the ensuing gunfight, Cardo shoots and kills BuCor Director Ladronio (King Gutierrez), one of the people who helped Don Emilio torture him.

However, Bruno is then captured by two corrupt policemen, Gapuz (Raph Fernandez) and Pantig (Pocholo Barretto), with Vendetta failing to rescue him, leading to his death.

Romulo tells Diana about the fight of his movement for their rights when they were in the mountains and laments to her how selfish, greedy, and wicked the people in power were.

Meanwhile, Alyana gives in to Marco's advances and starts a relationship with him, much to the chagrin of the latter's aunt, Menchu Versoza (Matet De Leon).