After an excruciating two-month mid-season break, addictive post-apocalyptic zombie series The Walking Dead returned last week in the aftermath of yet another crisis.
The core group of survivors were scattered across the countryside after a shootout left their former prison home ruined and overrun by flesh-eating walkers.
Last week's episode saw their injured leader Rick Grimes (Andrew Lincoln) and his son Carl reunite with sword-wielding warrioress Michonne, while promos for tonight's episode reveal Daryl, Beth, Glenn and Maggie, Tyreese, Sasha, Bob and children Lizzie and Mika are also still alive. But they're extremely vulnerable out in the open and alone or in small groups of two or three.
The fate of some characters - including baby Judith - still hangs in the air. Ever since the mid-season finale showed the infant's car seat left empty and covered in blood, her survival has been the biggest question left unanswered.
If this epic blend of drama, action, horror and nailbiting suspense has proved anything so far, it's that no one is safe in the brutal new world splendidly realised by creator Frank Darabont (The Shawshank Redemption) and special-effects maestro Greg Nicotero (Day of the Dead), among others.
With desperate survivors proving to be more dangerous than the undead, trust and kindness can be a weakness. On the other hand, people must stick together in order to have a fighting chance.
The characters struggle to tread the line between doing what is necessary to survive while maintaining their sense of humanity.
"It is (about) how human beings collide," says actor Chad Coleman, who plays Tyreese.
"Trust, humanity, betrayal, egregious violence, all the things on a lesser scale we deal with in this real world. So I think in a lot of ways this is a perfect form to talk about those kinds of things.
"This season four, you'll see a lot more of the character development . . . (and) those epic kinds of themes being laid out in a way that is incredibly compelling."
Speaking on the show's prison set just outside Atlanta, Georgia, while filming season four, Coleman (also known for playing Dennis "Cutty" Wise in cult TV show The Wire) describes Tyreese as a "big guy with a heart" who performs a major role in the fourth season.
Tyreese took a big emotional blow in the first half of season four when his sick girlfriend Karen was murdered by an unknown culprit, later revealed to be Carol, whom he trusted. He also almost lost his sister Sasha (Sonequa Martin-Green) from the influenza outbreak.
Originally an outsider, Tyreese has proved himself to be a useful member of the group. The beefy, former professional football player has a bad aim with a gun so favours hand-to-hand combat with the hammer as his weapon. "A character having an Achilles heel and someone of my size and physicality, why not? I find it far more interesting," Coleman says.
He believes Tyreese has been developed into "a fuller, a much more complicated character" from his original incarnation in the comic books by Robert Kirkman, Tony Moore and Charlie Adlard, from which the series is loosely based.
"You want to bring something a little bit more complex and something that the audience doesn't expect," he adds.
"I like it when the audience doesn't know which way you are going to go. That's what pulls them in on TV."