In the midst of this new threat, flashbacks show the events following Pete's execution, including Rick's new leadership role and reunion with Morgan Jones (Lennie James).

Black and white flashbacks present select events following the town council meeting where Reg and Pete were killed: Deanna berates Gabriel for turning her against Rick's group; Pete's oldest son Ron becomes alienated from his mother, Jessie; Glenn brings Nicholas in for medical treatment, concealing his actions; Tara awakens; Morgan and Rick reunite.

In the morning, Heath (Corey Hawkins) returns from a two-week supply run with his team of Scott (Kenric Green) and Annie (Beth Keener).

There, Morgan provokes Rick to question his conscience, and the duo discover the quarry where they deposit walkers accidentally attracted by Pete's oldest son Ron, who had followed them.

Grieving, Deanna has mentally checked out and effectively cedes authority to Rick, who voices his intention to free the walkers from the quarry and lure them 20 miles away from Alexandria.

Later, when an unarmed construction team is building a wall intended to turn the herd, Rick unexpectedly holds back his armed people and allows walkers to close in on some Alexandrians, in an effort to teach them to defend themselves with their tools at hand.

Carter runs to the front, thoroughly submissive and trusting his life to Rick's plan rather than his own judgement, but is grabbed and bitten on the right cheek by a stray walker unexpectedly trapped amongst the trees.

Corey Hawkins joins the cast as supply runner Heath, a prominent and long-running comic book character who is a loyal friend of Glenn Rhee.

[7] During the casting call, Heath was referred to as "Delvin", a "cynic [who] is left so dumbfounded by displays of stupidity that it's nearly impossible for him to admit that he thinks, down deep, people are – or at least can be – decent.

[9] Kenric Green, whose wife Sonequa Martin-Green plays Sasha Williams on the show, also joins the series as the comic character Scott, who is Heath's supply run partner and friend.

[10] Speaking with Tech Insider, Nicotero explained the artistic choice of using black and white for the flashback scenes, saying: "We took sort of a rather bold move because we wanted to play with our non-linear timeline.

We wanted to sort of make sure it wasn't confusing for the audience, so we had initially explored the idea of doing a desaturated flashback versus an oversaturated present-day.

"[11] Laura Bradley of Slate and Leah Marilla Thomas of Bustle both praised the use of black and white; however, many fans were mixed about the scenes and expressed their opinions on social media.

The critics' consensus reads: "A knockout opener to The Walking Dead's sixth season, 'First Time Again' has everything one would hope for - including intense plot development, entertaining character interplay, and more zombies than ever before.

"[15] Variety's Brian Lowry assessed that "The Walking Dead looks very much at the top of its game, with strong character material mixed with a massive set piece in the extended premiere made possible, no doubt, by its enormous popularity.

Blessed and cursed with a vagabond mentality, the first episode finds the gang still trying to fit into a gated community, where the promise of security is balanced against the cultural clash separating the battle-hardened travelers from those sheltered within.

[16] Brandon Davis of ComicBook.com praised the episode and felt that Andrew Lincoln gave his best performance to date, as well as its unique storytelling of shots in the past and present, while also singling out the character of Carol Peletier, writing: "Though not given a hefty amount of screen time, McBride's Carol Peletier remains a strong foundation for the group with her sly performance as the undercover post-apocalyptic friendly neighbor."

"[17] Writing for Hypable, Andrew Sims also praised the unique storytelling as "much needed" for a show that has five seasons under its belt and wrote: "[the] premiere offers fans one of the most exciting and original episodes in recent memory.

The episode is an incredible, complete package, as big as you'd want a 'Walking Dead' movie to be; but it also shows how things start off bad — and as usual, are only getting to get way, way worse.