TV preview: Line of Duty (BBC1, Sunday, 9pm), American Gods (Amazon Prime)

It’s testament to Jed Mercurio’s writing talent that, however far-fetched Line of Duty gets, there’s never a question surrounding whether or not you’ll be tuning in the following week. It always remains a certainty.

This latest run – more gripping than ever – draws to a typically dramatic close on Sunday with DCI Roz Huntley (Thandie Newton) now fully transformed into what is essentially a human version of the T-1000 from Terminator 2. So far she’s managed to cover up a murder, run rings around her squad and frame the father of her children for crimes committed by “balaclava man” whose identity still remains a mystery six episodes later. Will Huntley’s luck run out? The plates she’s been balancing are certainly in danger of crashing to the ground, that’s for sure.

So much happens in Line of Duty that it’s often hard to take stock of the events that will change the face of future series, one of which has been confirmed by the BBC (it’s tough to see the channel failing to keep it alive for longer still). The finale addresses such developments – one being DS Steve Arnott’s (Martin Compston) debilitating injuries suffered after getting thrown down a stairwell by that pesky balaclava man a few weeks back. Even the future of AC-12 – the anti-corruption squad at the heart of the show -–looks uncertain with ACC Derek Higgins (Brian Higgins) looking to pin the Caddy’s past crimes onto none other than extremely bemused department head Ted Hastings (Adrian Dunbar), somewhat implicating himself in the eyes of the viewer.

This fourth run may have seemed like a good starting point for newcomers, but last week’s episode tied current events to those introduced in the show's very first episode with such precision that it’s hard not to think Mercurio has orchestrated things meticulously from the word go. By the end of series four, all mysteries will be solved other than one – who could possibly ever follow in the footsteps of Westworld actor Newton and Keeley Hawes (Lindsay Denton) who have both provided British TV with two of its most engrossing female characters in recent memory?

To Neil Gaiman fans, an adaptation of his much-loved fantasy book American Gods has probably seemed like a long-time coming. Such is the novel's fantastical scope that not just anyone could have adapted beloved material such as this. Fortunately – judging by episode one, anyway – Bryan Fuller and Michael Green have pulled it off, bringing fans this new Amazon Prime eight-part series that excites as much as it confuses.

Former Hollyoaks star Ricky Whittle plays the show's lead Shadow Moon, a man serving three years in prison who is granted an early release when his wife Laura (Emily Browning) is murdered. One chance encounter with perennial scene-stealer Ian McShane's character Wednesday later and Shadow Moon's life has collided with those of the Gods that have incorporated themselves into American life.

If it all sounds bizarre, that's because it is. Fuller has utilised the visuals he fine-tuned in the untimely cancelled Mads Mikkelsen-starring series Hannibal and thrown in so much blood and sex that it's almost too easy to paint it with the Game of Thrones brush. That would be unfair – where that series started out setting its scene in a rather laborious manner, American Gods chomps at the bit to get to where it's going. Quite where remains to be seen, but if episode one proves anything, it’s that by the end credits you’re buckled in.

Granted, American Gods won't be for everyone but a sensory experience is close to guaranteed. For fans, the long wait seems to have been worth it – and for a series featuring a leprechaun named Mad Sweeney, how on God's earth could it not be?

Line of Duty airs on BBC 1 on Sunday. American Gods begins exclusively on Amazon Prime Video Monday with new episodes following weekly