The wife and daughter of Pittsburgh lawyer Frank Valera (Antonio Banderas), Sue (Cristina Serafini) and Olivia, are killed shortly after a talent show in which Olivia sings a song for Frank, and their bodies are dumped in a hole near the train yard.

After the funeral, Frank's father-in-law Chuck (Robert Forster) confronts him and tells him not to speak to him anymore.

After subjecting himself to beatings in an illegal mixed martial arts ring to atone for his perceived guilt for the murders, Frank is rescued by Pittsburgh Police officer Hank Strode (Karl Urban), whom Frank met earlier at the station.

Later, when getting involved in a fight to help a child prostitute, Frank falls through a window of a book store, where he fortuitously grabs Marcus Aurelius’ Meditations to help stop the bleeding of a leg wound.

He then takes a Stoic vow of silence until the case is solved and sets out to learn the skills required to do so.

After learning combat skills with masters of karate and Brazilian jiu-jitsu, Frank goes to the train yard, where the crime took place, to investigate.

A nurse, Alma (Paz Vega), arrives and brings him to her home to treat his injuries.

Frank then sneaks into the police station and finds that Hank Strode was assigned to patrol that particular district on the night of the murders.