The R of the title stands for the young protagonist, Rune, fearlessly played by Pilou Asbæk. Imprisoned for violent assault, he's a cocky, good-looking young man placed in the hardcore ward, where his survival depends on quickly learning the prison's parallel world of rules, honor, and obligations. R also stands for Rachid, a young Muslim prisoner who becomes Rune's friend and accomplice, defying the rigid racial stratifications among the inmates.

The two medicated low-lifes Carsten and Peter are long time partners, an old flame of Peter's turns up to tell him that he has a twelve year old daughter, whom he should present himself to. Her adoptive father is a mean bastard, and incestive undertones lies in the relationship between the two. The daughter escapes from her adoptive father, turns up at Peter's place, and Carsten, Peter, and the daughter escapes to Sweden.