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.

Pilou Asbæk
as Rune

Dulfi Al-Jabouri
as Rashid

Roland Møller
as Mureren

Jacob Gredsted
as Carsten

Omar Shargawi
as Bazhir

Kim Winther
as Kim

Jorg Beutnagel
as Bjørn

Sune Nørgaard
as Sune

Claus Poulsen
as Claus

Helmuth Kristensen
as Helmuth