The Walking Dead season 7 episode 4 review: The shape of things to come presented in pivotal episode

*Spoilers for season 7 episode 4 follow*

The news that the latest episode of The Walking Dead was to be feature-length may have injected the fear of life into you; this is a series, after all, that dispatched of two main characters - one all too flippantly - in the opening 30 minutes of its season 7 opener.

Breathe easy - the only thing you'll be mourning at the end of episode four 'Service' is normality; if the previous three episodes have been a prologue setting up what's to come, this outing is an introduction to a painstaking future that viewers never assumed these characters would face. In other words: the shape of things to come.

This week's episode plays out in real time from the moment Negan (Jeffrey Dean Morgan) comes knocking in the dread-filled opening sequence; "Little pig, little pig - let me in," he orders from behind the gates of Alexandria, his unmistakable silhouette enveloping the once Safe-Zone in a cloud of darkness. Some may think that Negan's on-screen counterpart is less effective with every appearance - it should be said actor Jeffrey Dean Morgan at times errs on the side of melodrama - but it's impossible to deny being on tenterhooks whenever he's prowling around our beloved characters, that unnerving Cheshire cat smile etched onto his face; whether it's staring down Rosita (Christian Serratos) lecherously or forcing Rick to hold his baseball bat, Lucille - still bearing chunks of Glenn's head, might we add - forget Shiva the tiger: in Negan, The Walking Dead has introduced a python that could strike at any time.

This episode's chief enjoyment arrives in his interaction with characters he's yet to meet, each encounter adding a layer of intrigue. For the past two episodes, The Walking Dead has run at a slower pace, and while exerting the same strength on the foot pedal, 'Service' flourishes in having more pawns to play with. Crucially, unlike episodes in the past, every character feels necessary which is undoubtedly due to the smaller character beats weaved in by writer Corey Reed. These moments include Father Gabriel's savvy decision to 'bury' Maggie (Lauren Cohan) to deter Negan from knowing she's actually at the Hilltop Colony right through to Rick's first candid admission that Judith is not his biological daughter, but Shane's - old character namechecks always earn a thumbs up. It's worth noting also how the religious former, played by The Wire actor Seth Gilliam, paves the way for the episode's standout moment - Negan's unnerved reaction to his appearance could register as the series' biggest laugh yet.

Some may be frustrated by not seeing the off-screen moment several characters learned of Glenn and Abraham's deaths, however, the subtle refusal to namecheck episode one's tragedies ends up touching stronger than these scenes ever could have (just let Enid keep those balloons, you decrepit Saviour, you).

Before we know it, we have a hostage situation on our hand thanks to two missing guns, inadvertently placing innocent inventory keeper Olivia (Ann Mahoney) in the firing line. This moment provides empirical proof that episode one's unpredictability has had the desired effect: if Rick doesn't bring the misplaced weapons to Negan, he will kill her - and you're certain he means it. The writers are evidently cruising in fifth gear now they're free to write for a character they've so clearly been waiting to get their hands on; you can practically hear them licking their lips. If they had their way, they'd probably make every season 7 episode a feature-length special.

While Rick is intent on abating his antagonist ("I'm no longer in charge," he solemnly states, "Negan is"), the unprecedented tough task on his hands is to keep his own people in line - in particular, the women. In a refreshing spin from the route most TV shows would head down, The Walking Dead's men are here depicted as the 'broken' figures while it's down to the female characters to sow the seeds of rebellion - namely Michonne (Danai Gurira) and Rosita (Christian Serratos). It's a sure bet Glenn's widow Maggie will gladly join their cause also.

Carl (Chandler Riggs), on the other hand, has no qualms about openly showing these Saviours his true feelings. As they ransack the residents of Alexandria's items, like a group of hoodlum looters, he fires a shot: "You should all just leave," he tells a visibly impressed, but no less furious Negan in a classic moment from the comic books, "before you learn just how dangerous we are."

Promisingly, producers have decided it's finally time to hand some characterisation the way of the aforementioned Rosita (Christian Serratos). Alongside Spencer (Austin Nichols) - the unsufferable son of Deanna who soon regrets expressing his distate of the pickle Rick's leadership has got them into - she is tasked by Dwight (Austin Amelio) to locate Daryl's motorcyle (yes, she finds it; yes, he takes it; yes, it's as heartbreaking as you're expecting). Outside the walls of Alexandria, she finds a group of deceased Saviours (now walkers) and nabs one of their guns. Later handing the motorcycle over to Dwight, he asks if she happened upon any other items: "Just your dead friends," she fist-pumingly retorts as the Saviours leave unaware they've left a gun in her mitts.

A sole gun may not be a lot but it seems that - in the hands of this scorned character, at least - one gun may be all she needs. Picking up the empty shell Negan fired earlier in the episode, she heads to chez Eugene and orders him to put his bullet-making skills to use. In poetic fashion, it seems Negan may have unwittingly sparked his own downfall. The rebellion has a lengthy distance to travel, but just four episodes into season 7, it's underway. Consider us buckled in for the ride.

The Walking Dead airs in the UK every Monday on FOX at 9pm.