Grace series 5 is significantly different to how the ITV drama began in 2021 when it was “the show about the cop with the missing wife”.

What had happened to DI Roy Grace's wife Sandy? That was the hook, what gave this show its uniqueness.

Grace wasn’t the drunk cop. Or the neurodiverse cop. Or the amputee cop. He was the cop whose wife had mysteriously vanished. He was the cop who was investigated for the murder of his wife. He was the cop who would never stop looking for his wife.

Then, at the end of Grace series 4, he found her.

As Grace series 5 kicks off, read on for a refresher on the shocking series 4 conclusion - and all the questions that need to be answered now.

How did Grace series 4 end?

Series 4 finished with Roy Grace learning the truth – or at least some of it – from the horse’s mouth. It was a hard truth to hear. It certainly wasn’t the reunion with wife Sandy he’d been playing on repeat in his head for years.

Roy also learned that he had a son – Bruno – he never knew about.

Then Sandy killed herself, leaving Grace to “keep an eye on” Bruno.

So, that was the end of all that.

Or was it?

A brief recap of Grace's missing wife Sandy’s plot leading up to series 5

First, some context. When we first met Grace in the show’s pilot, Dead Simple, four years ago, his wife Sandy has been missing for nearly 10 years.

We were told she'd vanished on his 40th birthday. “She went to work and never came home,” said Grace. “No signs, no warning, no note, nothing – just thin air.”

As far as Roy was concerned they'd had a happy marriage.

In the series two cliffhanger an old friend of Roy, Dominic Pope, called from Germany and told him: “I know this sounds utterly mad, but I think I may have seen Sandy. I think Sandy’s alive.”

Ultimately nothing came of this lead, and Grace started the process of declaring Sandy legally dead.

But viewers were given more insight than Roy. We learned that Sandy (played by Clare Calbraith) was alive and well, living in a commune just outside Munich, under the alias Alessandra M Lohmann.

We also discovered that she had a son called Bruno (at this point played by Marko Curteanu), and that she was unsure if Roy was actually the father.

She returned to Brighton and sneaked into Roy’s house in search of a DNA sample for a paternity test. While in Brighton she saw Roy and fiancée Cleo together.

Returning to the Munich commune with the results, she told one of the other residents: “When I saw Roy I realised, if I face him, I’ll no longer be the missing wife, the mystery. I’d be the villain who put her husband through hell.”

So Sandy intended to remain “missing”. But fate had other ideas. In a shock twist, Sandy was knocked down by a car on a Munich street.

Taken to hospital, Sandy was identified by Detective Marcel Kullen of the Munich Police, who’d been helping Grace with his search for his wife.

Roy headed to Munich. But a moment he always thought would be a reunion turned into a confrontation.

So what did Sandy tell Roy in the Grace series 4 finale?

Roy was shocked to discover that Sandy’s disappearance was all her own choice. However, she was frustratingly vague when it came to details.

“It became impossible for me to stay in Brighton,” she said. “To stay with you. And I couldn’t talk to you about it.”

She said she was having “dark days” adding: “You were never there. I was having panic attacks. Wasn’t sleeping. Found myself just… driving. Came to Munich and I just broke down. I… broke down.”

Grace was furious: “You left me? That’s what this is?”

He also demanded: “Was I really such a terrible husband? You actually wanted me to believe you were dead?”

When he flat out asked, “Christ. Was it really so bad?”, all Sandy replied was: “Leaving was better.”

And while Roy pleaded for specifics – “Tell me where you’ve been. You owe me that much, at least!” – Sandy remained light on actual facts.

Instead she just seemed more intent on pressing his buttons, at one point getting a real dig in: “It’s hard, isn’t it? Living on your own. Lonely.”

Even when Cleo confronted her, declaring, “Roy is a good man. He doesn’t deserve to be treated like this,” Sandy’s defence was typically vague, with her repeating: “I was broken.”

Sandy’s suicide note

Roy basically wiped his hands of Sandy, and returned to Brighton with Cleo.

But in the series 4 cliffhanger Roy received news from Detective Marcel Kullen that Sandy had killed herself.

Kullen emailed Roy Sandy’s suicide note.

In it Sandy admitted: “Leaving you like that was unforgivable. I wasn’t the person you thought I was. You were always so unflinchingly solid. Loyal. I was neither of those things.”

She also finally told Roy about Bruno. “When I left you I was pregnant. I had a boy, Bruno. He’s eight now… Roy, you are Bruno’s father. I’ve enclosed his paternity results with this letter.”

She also asked Roy to “keep an eye on our son. It hasn’t been easy for him. He won’t have to worry about me any more".

So exactly what must Grace unravel about Sandy and Bruno in series 5?

1. Sandy's affair with Cassian Pewe

There was one major omission from Sandy’s confession. In series 3, episode 3, Not Dead Yet, Sandy had a heart-to-heart with another member of the Munich commune, revealing her true identity and past.

“Roy was always working. I felt abandoned and I was angry. And then I realised I was pregnant and I didn’t know who the father was,” she said.

Later she revealed more specifics when she said that she was spotted by someone who knew her when she was in Brighton on her DNA-gathering mission: Grace’s boss, snide-y posh boy Cassian Pewe (Sam Hoare) – who at one point suspected Roy of murdering Sandy.

There’s no love lost between Roy and Cassian.

“Do you think he will say anything, the man who saw you?” asked the other member of the commune.

“Probably not,“ said Sandy. “But it’s complicated. For a while I thought he was Bruno’s father.”

Bombshell! So that was Sandy confirming she had an affair with Cassian, that Roy still doesn’t know about.

Even more worryingly, Sandy added: “One thing I do know, is that Cassian is selfish. He only reveals something when he stands to gain.”

And Cassian – who was seen at one point in series 4 secretly deleting CCTV footage of Sandy outside the Brighton police station – still has this card to play as of the start of Grace series 5.

So there’s at least one more piece of fall-out from Sandy’s disappearance to come. And there may be more...

2. Is Grace's wife Sandy really dead?

There’s an old adage about crime shows: never believe someone’s dead unless you’ve seen the body.

We never got to see Sandy’s body.

Now, it would seem incredible to think that Sandy could fake her own death, and Detective Marcel Kullen of the Munich Police seems to be about the most reliable witness you could find. It would also be incredibly callous when you factor in young son Bruno.

But there’s something oddly ambiguous about Sandy’s exit – a lack of 100% closure.

Plus, this is the woman – apparently on the edge of a nervous breakdown and not thinking straight – who managed to vanish off the face of the Earth so completely that even Brighton’s finest couldn’t follow her trail. Also, a woman who cut herself off completely not just from her husband, but her own parents. That's both immensely clever and callous.

Maybe Sandy is smart enough and self-justifying enough to traumatise everyone with a fake suicide.

And if that sounds outlandish, it’s nothing compared to Sandy’s twisty-turny story in the Grace novel They Thought I Was Dead. In this book author Peter James provided a very different backstory regarding what Sandy was up to in those ‘missing’ years.

We’re not going to give spoilers here, but you could argue that the TV Sandy and the book Sandy could have gone through the same experiences, it’s just that TV Sandy isn’t owning up to them.

Certainly the novel gave a much more plot-driven trigger for Sandy’s initial disappearance, rather than just feeling overwhelmed. Could we learn that there was something else that made her go AWOL in the TV show too?

On the other hand, as John Simm has said in interviews: “We’ve started to veer away from the books.” So don’t expect the show to follow the books.

3. The secrets Grace's son Bruno must be sitting on

Series 5 opens with Bruno in Brighton, being looked after by both Grace, and Sandy’s parents. It’s a difficult situation as Grace and Cleo have just lost a baby.

Another dangling plot threat is Sandy’s prior hint that "it hasn’t been easy" for Bruno (who in series 5 is recast, and now being played by Finn Guegan).

We actually know very little about what life’s been like for Bruno and you have to suspect that he may have one or two revelations to drop into the plot.

Grace series 5 airs weekly on ITV1 on Sunday evenings at 8pm, starting April 6. All four episodes are available on ITVX now.

You can also watch seasons 1 - 4 on ITVX.