Orange is the New Black entered unchartered territory at the end of season four. For large periods in the finale, the trademark dour humour was nowhere to be seen, and the show’s tone, which usually straddles the line between drama and comedy so expertly, took a seemingly irreversible turn towards darkness.

This development had been coming. In season three, the prison was privatised after a takeover by MCC. And prison began to seem less like a “bad day in high school”, finally reflecting the sensitive but seismic social issues that plague the penal system in the US.

Litchfield penitentiary became overcrowded, and the prisoners’ quality of life dropped dramatically. One inmate was raped, another was put in solitary. Season four then built upon this by shining a light upon systemic racism. White guards threw around racial slurs, black and latino people were prevented from congregating together. Piper Chapman (Taylor Schilling), once a self-righteous New York yuppie, became entangled with a group of white supremacists in a bid to maintain the power that she had earned since entering the prison.

But the death of Poussey Washington in episode 12, a beloved African American inmate crushed under the weight of inexperienced white CO Bayley, marked the real turning point: an irreversibly dark moment that will surely inform the tone for seasons to come. It was the breaking point for the issues of racism and dehumanisation of prisoners that had bubbled under the surface throughout the first few seasons.

Controversially, it found inspiration in the real world, the death scene echoing the tragic real-life death of Eric Garner in New York in 2014.

With season five comes the follow through that justifies this move into real-life drama. Season SPOILERS to follow.

Poussey’s killer is inexplicably let off the hook, and the fallout from this becomes the driving force behind the new season, which builds itself around a localised faction of the Black Lives Matter movement, led by Poussey’s best friend, Taystee.

Standing at the steps of the prison speaking to the press in the midst of a full-scale riot, she finally gives voice to the systemic racism that has been palpable throughout the series.

“Our fight is with a system that don't give a damn about poor people. And brown people. And poor brown people.”

It feels like a breakthrough moment: it is the first time that the prisoners’ grievances have been aired to the outside world, but it is also the first time in the show’s history that the greater good has come ahead of personal gain. Throughout its run the excellently drawn characters have often fought one another in order to get ahead. In season five, for at least a moment, a faction is united in the fight for a common good.

Of course, the prisoners still manage to let us down, even in the face of great injustice.

When Taystee arranges a vote to coordinate their demands list, she is enraged to find that the prisoners have listed other priorities ahead of ‘justice for Poussey’, including access to cheetos and tampons.

As recent history has taught us, democracy does not always lead us where we would like it to. Or, "Democracy is bulls***", as Taystee puts it.

Showrunner Jenji Kohan’s greatest trick is her ability to depict her characters warts and all, and still keep us invested. Each member of the sprawling cast is intrinsically flawed and often clamouring for self-preservation, and we become enamoured and disgusted with them in equal measure. Even the show’s heroine Piper has shown her dark side several times, most jarringly pummelling fellow inmate Pennsatucky half to death at the end of season one.

Yet it’s difficult not to root for her reunion with Alex Vause, and we’re happy to see her getting behind the “justice for Poussey” movement, even if it is just another cause to her.

But this season it is the humanisation of the bad guys that really hits home, even through some of the show’s darkest moments. Two such tales run alongside the main narrative: Piscatella’s origin story, which goes a long way to understanding what turned him into the abusive CO he is today; and that of CO Bayley in the aftermath of Poussey’s death.

Piscatella is the closest thing the show has to a straightforward villain. In the relative freedom of the riot, he is at his worst, performing an unconventional prison break-IN in order to torture his adversary Red. A fantastic episode in which he skulks throughout the corridors (the camera switching to first person), picking off the inmates one-by-one in a clear homage to 1980s slasher flicks, turns nasty as he attempts to destroy the respect she commands by shaving her auburn locks in front of her closest friends.

Yet in a flashback in another episode he becomes a figure of sympathy: It feels like Kohan wants us to back his decision to torture an inmate in his former workplace who had beaten and sexually abused Piscatella’s lover. At which point is this behaviour acceptable?

Similarly, we are forced to sympathise with Poussey’s killer. Visibly guilt-stricken, he makes a series of attempts to absolve himself of his grief, including suicide and turning himself in to the police, but is unable to escape the situation. He visits his victim’s father, who refuses to give him closure.

“There is no making it right,” Poussey’s father tells him. “ I’m not interested in giving you whatever it is you think you need so you can atone.”  

“May you never have a day’s peace. Never," he adds, before shutting the door in the weeping officer’s face.

Poussey’s death is tangible elsewhere throughout the season: grief hangs like a spectre over the prison and its inmates. At one point, a grieving Suzanne delineates a no-walk zone in the cafeteria where her friend’s body had once lain, and attempts to talk to her friend on the other side. With their newfound control, some of Poussey’s friends turn a section of the prison into an open library (Poussey had been Litchfield’s librarian), hanging books from the ceiling in her memory.

But it is through a pushback against growing injustice that the absence of one of the show’s most beloved characters pushes the show onward, into new and exciting territory. The riot is a formal innovation that shrugs off the staleness that had been developing in earlier seasons, and provides a platform for delving deeper into the social issues at its heart.

It’s the impetus for the show’s reflection on the Black Lives Matter movement, led by a distraught but empowered Taystee, with Danielle Brooks putting in a staggering performance as a surrogate lead, as Taylor Schilling’s Piper Chapman fades into the background.

Such matters merit delicate portrayal, and, much like the powerful death scene in season four (directed masterfully by Mad Men creator Matthew Weiner), it is handled with admirable care and subtlety.