Following the assassination of General Antonio Luna, Gregorio "Goyo" del Pilar, a young and brash brigadier general, has been tasked by President Emilio Aguinaldo to hunt down Luna's loyalists who have been charged with treason. One such soldier, Major Manuel Bernal, is captured at the house of Mariano Nable José in Dagupan. Bernal is tortured into rejoining the army, but defiantly refuses and insults Goyo, calling him a "dog" for his loyalty to Aguinaldo; Bernal is then executed. Aguinaldo then promotes Goyo to major general of Pangasinan. With a relative decrease in hostilities, Goyo, along with his older brother Julian, his friend Colonel Vicente Enriquez, and photographer Joven Hernando, spends the entire summer in Dagupan attending festivals and courting Remedios, Mariano's daughter.
Meanwhile, Aguinaldo approaches former prime minister Apolinario Mabini and offers him to rejoin the government as chief justice, which he reluctantly accepts (later in the film, the appointment never materialized). When Mabini asks Aguinaldo about Luna's death, he deflects the question. Elsewhere, General José Alejandrino, Luna's former ally spared from the purge, goes to Manila to negotiate with the American Generals Elwell Stephen Otis and Arthur MacArthur Jr. who both refuse to recognize the sovereignty of the First Philippine Republic unless the Filipinos surrender. The negotiations failed and the war intensified. Unable to launch a counterattack, Aguinaldo orders the army to retreat to the Cordillera Range with Goyo commanding the vanguard. During the long and exhausting march through the mountains, the army is plagued by persistent American attacks, internal tensions from Luna's old unit, as well as hunger and disease. Goyo is further pressured when Aguinaldo's mother and son are captured.
The army arrives at Mount Tirad, where Goyo devises a delaying strategy that will give Aguinaldo and the rest of the army enough time to escape. Together with Luna's former soldiers, including former Luna Sharpshooter Lieutenant García, fortified trenches are dug on the slope overlooking the mountain pass. On December 2, American troops under Major Peyton C. March arrive. The Battle of Tirad Pass begins and the Americans are initially unable to penetrate the Filipino defenses. With help from a local guide, the Americans use a secret path to outflank the Filipinos. Having just overcome the PTSD he developed in earlier battles, a rejuvenated Goyo attempts to turn the tide of the battle but is suddenly shot dead by an American sniper. Learning of Goyo's death, the Filipinos' morale breaks down and they are easily overwhelmed. Joven and García's son Kiko flee but Joven falls off a cliff after encountering an American soldier. In the aftermath of the battle, the Americans strip Goyo's corpse for war trophies. Goyo is then buried on the site which is soon visited by Vicente and Lieutenant Telesforo Carrasco, who both survived the battle, and Felicidad, Goyo's former lover and Aguinaldo's younger sister.
Two years after the battle, Aguinaldo is captured by the Americans in Palanan, effectively ending the war. Held as a prisoner of war in Malacañang Palace, Aguinaldo is visited by his former aide-de-camp Manuel L. Quezon, who has surrendered to the Americans on the orders of his commander, General Tomás Mascardo. Quezon consults Aguinaldo on whether Mascardo should surrender, to which Aguinaldo replies that it is up to Mascardo to decide. Meanwhile, Mabini is also captured by the Americans and exiled to Guam where he writes down his own narrative of the war, La Revolución Filipina ('The Philippine Revolution') which notes Aguinaldo's failure as leader of the Philippines.
In a mid-credits scene, Joven is rescued by Kiko and Eduardo Rusca, Luna's former aide. Decades later, both Aguinaldo and Quezon ran for president in the 1935 election, while an older Rusca and Joven gave a mocking salute to the dismayed Aguinaldo.
