If you missed series one, the story revolves around single mother Alex Drake (played by Keeley Hawes), who in the 21st century has risen rapidly through the ranks of the Metropolitan Police. After being shot, Alex wakes up in 1981, surrounded by familiar faces from a very different era.
Series two kicks off in 1982, six months on from where the first series left off. Sexual equality has yet to surface and along with trying to work out how to get back to 2008, Alex has the politically incorrect DCI Gene Hunt and his team to keep in check.
"Alex Drake is starting to accept where she is in the 80s world but that all sort of gets turned on its head in this series. What she thinks it's all about and what it actually is are two different things," says Marshall Lancaster, who plays DC Chris Skelton.
Marshall is reprising his role, alongside Philip Glenister (DCI Gene Hunt) and Dean Andrews (DS Ray Carling). The trio all starred in the show that started it all, Life On Mars, where John Simm played cop Sam Tyler, who awoke in 1973.
"I think Chris has moved on but I don't think Ray's shifted much at all," 34-year-old Marshall says in his strong Macclesfield accent.
"Gene Hunt's changed a fair bit. He's had to conform to how the system's starting to work. You can imagine how they used to say, 'oh, it's started turning all these old-style coppers into dinosaurs'. He's battling against it but he sort of changes for Alex Drake, who he likes. He can't knock seven bells out of her like he did with Sam Tyler."
As for his own character - "he's a complete idiot," Marshall laughs.
"He's a sensitive soul, he's a try hard," he adds.
In this series, we see his relationship with feisty WPC Sharon "Shaz" Granger develop and there's even talk of wedding bells.
"He's a bit of a romantic really but stuck in a sort of 70s, 80s frame of mind," says Marshall.
"So like with Shaz, she's quite a modern girl really for her time and Chris can't always see when he's upsetting her or saying the wrong thing, you know, when he's being a bit chauvinistic. It's all done purely innocently."
It's in his quest to redeem himself yet again that Chris does a striptease for Shaz in front of the entire team in the opening episode.
"That caused me a lot of sleepless nights," Marshall says.
"I was just thinking I haven't got the equipment to be doing this!"
"I had to do a scene before and I was that nervous I just couldn't get my words out because I was thinking I know what I've got to do in 10 minutes."
But as with any challenging scene, he just had to throw himself into it.
"I got sent to a stripper to have a sort of class and I sort of picked up moves from her but then as it went on, I started doing my own belt whipping moves and things like that."
"I mean, not to get too arty farty about it, at the end of the day it's just taking me kit off but I tried to base it on a woman's striptease, rather than a man's because that's the whole point, male strippers hadn't come into fashion. There wasn't The Chippendales or anything like that, so I had to base my moves on what a woman would do! It was just horrendous. I'm scarred, that's all I can say!"
Stripteases aside, it's Chris's fashion choices that make him truly stand out in this series.
"I've had no end of stick about my highlights to be honest with you. The first thing Phil said to me was, "What's happened there? Has a bird s**t in your hair?"
And then there are those trousers.
"This time they've either been really, really skin tight and I've had to go running around London most mornings to make sure I fit into them. Or they were like those really baggy style, silvery ones with the high waist belt that would put Simon Cowell to shame."
Marshall admits the whole cast enjoyed wearing 80s clothes to get into character.
"It's so strange because even just after a week, you just start accepting it. You're out on location and filming somewhere in the street and you're just wondering why people are looking at you. Then you remember Dean's got his 'tache and perm and I've got these highlights."
The Ashes To Ashes car, a red Audi Quattro, has also taken on iconic status.
"It's great when Phil's driving the Quattro round and we have a good laugh in the car," Marshall says.
"Whenever we're filming people normally see the car first and then know the show immediately just from seeing the Quattro."
It's this banter both on and off screen that makes the job so enjoyable.
"It's always been good," Marshall says.
"They're long, heavy days so you can get on each others' nerves sometimes, but for the majority of the time we're laughing and joking."
He says the show's two female leads can hold their own in the testosterone-heavy environment,
"It can be very manly at times but it sort of suits the show because in a way that's what Alex and Shaz are battling against, so we sort of encourage it."
Marshall Lancaster - Extra Time
Marshall was born in Macclesfield, Cheshire, on October 5, 1974.
Before his big break in Life On Mars, Marshall worked on a milk van by night and walked dogs by day, calling himself 'The Dogfather'.
Marshall acted alongside John Simm in The Lakes and Philip Glenister in Clocking Off before meeting up again in Life On Mars.
He's set to reprise his role as the "dirty, sloth type" Slug in Coronation Street this summer.
He admits to being a bit of a recluse when TV shows he's in are on air.
"I'm glad that people enjoy the show but I often feel like I shouldn't be there."