In a bombing attack, officers from a Border Guard unit in the Bieszczady Mountains are killed. Only one of them survives. As a result of the attack, Captain Wiktor Rebrow loses not only his friends, but above all his beloved Ewa. Lost and devastated, he tries to find out what really happened and who is behind it all. His superiors are also determined to uncover the truth, while the official investigation is led by the prosecutor’s office. The story takes place in the Bieszczady — a place both magical and dangerous. The titular “pack” stands guard over Poland’s eastern border, the external border of the European Union, where people, drugs, and weapons are smuggled — for money, profit, and sometimes for a chance at a better life. Every border guard swears to protect the sovereignty and integrity of the state’s borders, and to safeguard the interests and security of its citizens.

Four years have passed. The borderland remains unstable; more and more people are crossing the border illegally, and the Border Guard operates under enormous pressure. Prosecutor Iga Dobosz (Aleksandra Popławska) returns to the Bieszczady to lead an investigation into a gruesome crime. Markowski (Andrzej Zieliński), who keeps the unit under firm control, has earned the trust of his subordinates, but the events of the past continue to haunt him. Grzywa is dead. Rebrow (Leszek Lichota), pursued by the justice system, is hiding deep in the Bieszczady wilderness. He struggles against the harsh natural environment and remains in contact only with two friends — Łuczak (Jacek Lenartowicz) and Marta (Anita Jancia-Prokopowicz). Everything changes when an undocumented immigrant, Alsu (Anna Donchenko), appears at his hideout.

The third season begins when the Border Guard detains two migrants attempting to flee from Poland to Ukraine. Following their trail, Rebrow unexpectedly discovers a crime scene. The brutal murder sends shockwaves throughout Poland. Markowski launches an investigation, while Rebrow turns to Dobosz for help, suspecting that the case may have deeper, hidden layers. Climbing the career ladder in Warsaw, Dobosz reluctantly returns to the Bieszczady.