It’s floating in the mangroves, waiting for hard-bitten detective Jay Swan (Aaron Pedersen) to find it: a headless corpse caught in fishing nets. This gruesome discovery is made early in the first episode of Mystery Road season two, marking the arrival of a new case for the franchise’s Akubra-wearing outback sleuth to solve.

Across a long narrative arc encompassing the 2018 six-part series directed by Rachel Perkins and two earlier feature films directed by Ivan Sen (2013’s Mystery Road and 2016’s Goldstone), Jay’s investigations have ventured into some very dark places – including homicide and missing person cases, political corruption, people trafficking and drug syndicates.

The new series is directed by two highly distinguished Indigenous Australian film-makers: Warwick Thornton (Samson and Delilah, Sweet Country) and Wayne Blair (The Sapphires, Cleverman). It is set in the fictitious coastal town of Gideon, captured by Thornton – also the cinematographer – in the real-world locations of Broome and Western Australia’s scenic Dampier Peninsula. Thornton and Blair depict Gideon as a place on the edge of existence, populated by broken souls: people who are hiding; people who are starting again. One of them is Jay’s ex-wife, Mary (Tasma Walton), who is dating a semi-retired police officer, Simon (Callan Mulvey).

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Law needs to be followed here, as the snitchy senior cop Owen (Mark Mitchinson) stresses to Jay, their fractious relationship drawn from the familiar interplay between the stop-at-nothing investigator and the weary, harrumphing superior. But there is also lore: traditional knowledge, beliefs and stories drawing a longer line across history.

The screenwriters (Steven McGregor, Blake Ayshford, Timothy Lee, Kodie Bedford and Danielle MacLean) explore this in a subplot involving a Swedish archaeologist Sandra (Sofia Helin), who visits Gideon to dig up ancient artefacts, to the chagrin of some locals. Jay’s new partner, Fran (Jada Alberts), is called to the dig site to address a conflict involving an angry protester – her sister, Leonie (Ngaire Pigram).

Leonie dismisses Sandra’s argument that she is rewriting history. “I know my history,” she says. “I don’t need you or anyone else to dig it up.” She then turns to Fran and says: “This is your country too. Which law you stand for?”

This short exchange captures Mystery Road’s extraordinary breadth. This series reflects on aspects of the national ethos in ways no other detective serial can, reinvigorating tried-and-tested genre templates with fresh Indigenous Australian perspectives. The core of the show reflects through fiction what SBS’s recent, thrillingly revitalised view of Australian history, Australia in Colour, captured in documentary: the idea that this country is only just beginning to come to terms with its past.

The idea of unearthing neglected truths is made literal at the dig site, which has ancient as well as immediate significance when a gruesome discovery is made there too. It is connected, like the headless corpse, to what appears to be a large-scale drug manufacturing operation, potentially involving a local pearl farmer and former special forces soldier (Gary Sweet).

Mystery Road was at its most politically charged and polemical in its second film, Goldstone, which opened with a montage of sepia-toned photographs taken from the gold rush, juxtaposing images of Aboriginal people in the dirt and mud while white folk eat large meals around dinner tables and go on camel expeditions – one sitting with his hand on an Indigenous man’s head, as if it were an armrest. The centring of Indigenous Australians in both narrative and above-the-line creative roles has brought to it an authenticity and urgency unmatched by any other Australian crime series; perhaps any Australian series full stop. The genre format makes it palatable for the masses, the previous season even winning a Logie award for most popular drama.

Mystery Road season two is less direct than Goldstone in its interrogation of colonialism. It contemplates the profoundly difficult question of how to reconcile Indigenous heritage with a modern, white person-oriented society, with its Judeo-Christian foundations and genocidal past. This has emerged as a fascinating recurring theme in 21st century Australian film and television, memorably explored – using the enigmatic language of contemporary dance – in Spear, the 2015 feature film in which Pedersen delivered another high-impact performance. He played Suicide Man, a desperate, sweat-drenched homeless person who yells at passers-by in an underground train station. This character was inspired by the tragic story of a real-life person the film’s director, Stephen Page, described, in an interview with Guardian Australia, as having “had a foot in talking lingo to his mob, and a foot in talking to the corporate people in Perth. The front of him was a business suit, the back of him just a painted back of ochre.”

We see this notion of dual identity explored in a less abstract way in the penultimate episode of this new season of Mystery Road, when Jay confronts the formidable senior lore man Jimmy Two, played with menacing charisma by Stan Yarramunua. In a rousing monologue that channels what the academic Marcia Langton once described as “ties that inscribe self in place and place in self”, Jimmy points a large stick into the distance and says: “You see them trees out there? See them rocks? That water? That’s me. We’re one. Where’s your tree? You poor thing. You think that badge is your law, ay?” Later Jimmy adds: “I’ll answer to my law, my people. White law means nothing.”

There is no way of knowing, given the dialogue is delivered orally, whether he is speaking about law, or lore, or both. Jimmy is grappling with a philosophical conundrum that has long confronted Jay – presumably since he initially entertained the idea of working for the police. He has much to contemplate and many crosses to bear. Like in the previous season, family matters also challenge the protagonist and complicate the case, with Mary becoming increasingly entangled in the investigation into the drug ring.

Related: Aaron Pedersen: is the Mystery Road star one of the greatest actors of his generation?

The detective genre is filled with stories about morally conflicted people embroiled in tricky situations. For Jay, moral and philosophical conflicts don’t come and go when cases open and close; they are intrinsic to his sense of self. As a police officer discriminated against because he is black, and as an Indigenous man distrusted within the Aboriginal community because he enforces white law, he is caught between traditions, between worldviews, between laws and lores. In one sense Jay’s character is tied to genre heritage – from a long line of obstinate gumshoes – but he is also light years from celluloid ancestors such as old school Bogart-like types, wooing dames and dry-gulching cronies.

Pedersen’s performance radiates gravitas, simultaneously projecting great strength and great sorrow. Emotional stoicism occasionally gives way to outbursts of rage and indignation, suggesting a deep-seated conflict simmering in his psyche and at the heart of Mystery Road’s narrative. The escalating arc of that conflict can be felt throughout the new series, which begins with Jay as crotchety as ever, then slowly, skilfully, patiently ratchets up the tension, pairing the growing intensity of his feeling with the increasing danger of his circumstances.

There are shock twists, car chases and confrontations with villains. The action scenes have a real kick to them – but it’s the depth and scope of the script that keeps you thinking long after the credits roll.

• Mystery Road season two premieres on Sunday 19 April at 8.30pm on ABC and will be available to stream on iView