“Temptation is the source of all suffering,” Sidney Chambers (James Norton) tells his congregation as they gather in the church, his words – as always – setting the scene for what’s to come during a 60-minute trip to that picturesque parish of Grantchester.

Geordie’s (Robson Green) temptation finally takes its toll on poor old Cathy (Kacey Ainsworth), whose grand night out at the policeman’s ball is ruined when newly appointed Sergeant ‘Suck Up’ Phil (Lorne MacFadyen) decides to get his own back by revealing details of his superior’s extra curricular activities with police secretary Margaret (Seline Hizli). 

We told you all his staring at the office door when the pair were up to no good wasn’t normal.

Grantchester series three recaps

It’s an absolutely heartbreaking discovery for Cathy – and an ace performance from Ainsworth – who’s left to ponder whether her marriage has a future. “You bought me a food mixer, you bought her a necklace. Do you love her?” she asks Geordie while sobbing in their bedroom.

Pity he didn’t buy her a nice new iron. She’s got form for delivering just desserts to ne'r-do-wells with one of those, after all.

Speaking of husbands who definitely don’t deserve their wives, the return of Mrs Maguire’s mysterious Ronnie gives Tessa Peake-Jones the chance to showcase her talents.

Charlie ‘estranged husband’ Higson (Broadchurch’s Ian anyone?) steps in as the sneaky Ronnie, who rolls into town with a tale of a cancer diagnosis and a life spent rambling the countryside upon his return from the war.

Mrs Maguire is rightfully reluctant to let him into her life at first. “You’re full of sh*t, Ronnie,” she spits, showing off a dark side we most definitely want to see more of. 

As the pair spend more time together it's clear that the lady might just be for turning, albeit only ever so slightly. But this is Grantchester, so just when you think the housekeeper might have found some closure, it’s revealed that her husband is actually a lying, cheating cad who doesn’t have cancer at all.

And of course she only learns this after he’s made off with her locket and all of her savings.

Her suffering is almost too much to handle, but the most heartbreaking moment of the episode is reserved for Al Weaver’s Leonard.

For weeks now we’ve watched him struggle with his sexuality after the Archdeacon (Gary Beadle) basically instructed him to straighten up and find a wife, and as old flame Daniel rolls into town for the engagement photos everything comes to a head. 

A discussion about sex during an ill-fated night of babysitting with his wife-to-be forces Leonard into a corner, and when he’s challenged about his desire to marry – “I don’t want to be someone’s mistake” says Hilary (Emily Bevan) – his wounded one-time bride’s words hit him where it hurts.

The pressure is all too much for Leonard, who retreats to his room and takes out a razor blade with trembling hands. By the time Sidney finds him he’s thankfully not gone through with the plan to take his own life, but what ensues is no less heartbreaking.

“I can’t even do this right,” Weaver sobs, reminding us that he’s Grantchester’s not-so-hidden gem as he delivers his dialogue with all the pain and heartbreak of a man whose own beliefs are so at odds with his very being.

“You can only be who you are, Leonard. You can’t fight who you are,” Sidney soothes, all the while fighting who he is and attempting to stop crime at the same time.

This week’s investigation into the death of a young girl on her pious factory boss Ezra Garston’s (Christopher Fulford) premises opens a whole new can of worms. The vicar and Geordie don’t take long to solve the mystery – it was the boss’s son what dunnit, and actually it was an accident – but the local Masonic Lodge prevents them from serving justice.

You see Supt. John Baldwin (Adrian Lukis) is one of the gang and he’s not opposed to doing favours for his fellow Masons. Phil (shock horror, he’s in on it, he knows the handshake and everything) isn’t quite so comfortable with the idea though, so he slips Geordie enough evidence to allow him and Sidney to force Garston to keep paying for the upkeep of the dead girl’s son.

By the time the investigation has concluded Sidney’s had enough. Enough of seeing his friends heartbroken, enough of struggling with his love for Amanda, and enough of the righteous church he had been prepared to devote his life to.

“What do you want Sidney?” asks a frustrated and disappointed Amanda. After a bust-up with the booming Archdeacon it becomes very clear that the vicar has absolutely no idea, and that he can’t turn to the man upstairs for answers. 

In fact he turns his back on the church instead, dropping the dog collar, putting on his jacket and strolling out of town.

Can Sidney be tempted back to his church? Only time – and next week’s episode – will tell.

Grantchester continues on ITV on Sunday nights at 9pm