Although "feminine" is thrown around like the dirtiest F-word, the deadliest fighter in the dojo is the ferocious Anna (Imogen Poots), the most interesting character in the film. On the journey into a heart of darkness, Anna goes farther than any man into the depths of her trauma and rage, while it turns out Casey is merely the empty cipher at the center of the story. When the film ultimately goes completely off the rails and then comes around to a female-empowering conclusion about finding strength in compassion, it feels half-baked and tacked on at best.