Drug lord Alonso Marroquín is in a Mexican prison waiting to be extradited to the United States, but the DEA and the prison warden have other plans for him.

When Marroquín reunites with his son, Lucas, he realises that being a father is more difficult than running a criminal empire; Becerril realises they underestimated their opponent; the effects of the US Army's secret experiment keep spreading.

Snowman's plans to expand his experiments take an unexpected turn; Lilia decides to interview the world's most wanted fugitive; DEA agent Taft breaks the chain of command and sets out on a personal quest; Lucas disobeys his father's orders.

The zombie army recruits new members; Marroquín discovers that one of his men is a traitor, and a new danger hunts Lucas, who realises that something strange is happening; Becerril gets closer to his human enemies.

When Snowman's experiments on an infected human fail, Murdoch agrees to get more human subjects; Agent Taft discovers a clue about Marroquín; Lilia escapes from an enemy thanks to Dávila's help.

A zombie is tormented by his human memories; a secret mission ends badly when the US Army Rangers face an enemy that seems bulletproof; Valencia must break an oath; Romeo is hunted by his own past; Chainsaw uses his abilities to capture a monster.