Back in 2013, the first series of Broadchurch justifiably gripped the TV nation. Writer and creator Chris Chibnall (soon set to take over from Steven Moffat as showrunner on Doctor Who) crafted a riveting drama with an emotional weight that raised it far above the average murder mystery.

Then series two spluttered into existence two years later, marred by too many messy competing storylines and an unsatisfying conclusion. Can this third and final season rescue Broadchurch's reputation?

After a sweeping shot of those now iconic cliffs, the opening episode of series three focuses in on a lone figure sitting outside an empty police station. Trish (Julie Hesmondhalgh, ex of Coronation Street) is bloodied, bruised and beaten down, the victim of a serious sexual assault. DI Alec Hardy (David Tennant) and DS Ellie Miller (Olivia Colman) arrive and Trish is swept up in the workings of a rape investigation. Emphasising the forensic detail as photographs are taken, wounds catalogued and clothes logged and sealed in evidence bags, it's never voyeuristic but highlights how thorough the police need to be, adding another dehumanising layer to the experience of anyone who reports a rape. Her first question – 'do you believe me?' – hangs heavy over the entire episode.

We briefly meet some of the new (including Lenny Henry and Sarah Parish) and returning (Andrew Buchan and Arthur Darvill) faces but the first half of the opening episode concentrates solely on Trish, Hardy and Miller. It's a smart move focusing our attention on the case and building an emotional connection with Trish. So it's hard to judge the full impact events will have on the wider community as the series continue, though having Beth Latimer (Jodie Whittaker) as a counsellor assigned to Trish's case feels like a convenient coincidence.

Broadchurch is about slow steady police work, painstakingly sifting through clues, and highlighting the impact of a violent crime on society, not just the hunt for the culprit. Hesmondhalgh – who, as Corrie's Hayley Cropper, was the first transgender character in a British soap opera – invests Trish with a shattered realism, making her a complex rounded human being rather than an anonymous victim.

Tennant's world weary expression and constantly roving eyes perfectly capture Hardy's mind, constantly looking for angles and processing information. But Colman is once again the star player. Despite having the optimism knocked out of her by events in the first two series, she brings humanity, strength and determination to Miller, one of the most brilliantly realised and affecting characters on mainstream TV.

First and foremost, Broadchurch is still a thriller. Chibnall never forgets the classic whodunit formula, raising several niggling questions that will itch until they are resolved. It's a great start – let's hope it can take us into the final stretch with as much understated elegance as this engrossing first episode.

Broadchurch season 3 starts on ITV, Mon 27 Feb, 9pm.