Westworld fans react to game-changing season 4 episode

*Warning: This article contains major spoilers for Westworld season 4*

Westworld is no stranger to flipping the script on its audience, but the latest episode of season 4 proved that and then some – and fans can't get enough. After episode 4, titled 'Generation Loss', aired in the US on Sunday, July 17, many viewers took to social media to praise the game-changing installment, admitting that they hadn't been this excited about the HBO sci-fi series since the first season.

In it, Tessa Thompson's Charlotte Hale – a vengeful version of Dolores – reveals to Aaron Paul's Caleb Nichols that he isn't actually a human, he's a host, and that he's been dead for 23 years. The timeline which sees Bernard, Stubbs, and their new acquaintance Frankie – who we now know is Caleb's grown-up daughter – is set in the apocalyptic future, while everything that's been happening with Maeve and Caleb was technically in the past, as the latter was forced to relive the events leading up to his death. (We're still none the wiser on Evan Rachel Wood's Christina).

Anyway, Caleb was actually killed by Hale's goons when he and Maeve later tried to stop her from using parasitic flies to control the human guests of the Delos parks. In a brawl with the Man in Black (Ed Harris), Maeve (Thandiwe Newton) blew herself and the rival host up – a visual so shocking, it causes an onlooking Caleb, who was already bleeding out from a stab wound admittedly, to pass out. When he comes to, Hale starts goading him as to what happened after, which prompts Caleb to remember that he didn't actually make it out alive despite Maeve's sacrifice.

"I'm me,” a bewildered Caleb states, as Hale chillingly replies: "You're certainly a version of you. The 278th, I believe." It becomes clear that the duo failed to thwart her terrible plans, then, when Caleb – having now awoken in the real world – finds himself in a glass room. He escapes out into the New York City street, where he hears a loud noise coming from a tower. Everyone around him freezes, and Charlotte walks over to him. "Welcome to my world," she says ominously.

"Tessa's performance. Aaron's performance. Maeve/Caleb. The writing. The reveal. All just so good. This season might be my favorite," one fan wrote on Twitter, as another tweeted: "Anyone who bailed out on Westworld made a huge mistake. This is the best show currently in production and season 4 is absolutely amazing. It justifies an HBO Max subscription all on its own."

"#Westworld just aired it's best episode of the season and the best episode since season 1. A complete jaw dropping experience," a third gushed. "Aaron Paul proves why he is one of the best actors working currently. The twist and turns this one had was shocking. Start watching this ASAP. Just WOW."

Check out some more glowing reactions below...

Emotionally, the twist regarding Caleb's death packs a punch, largely due to the fact that the episode sees Maeve and Caleb reflect on the time they shut down the final copy of Rehoboam. On the mission, Caleb was gravely wounded, but Maeve got him to a hospital in time and he made a full recovery. It was then that the twosome parted ways, with Maeve choosing to go into hiding and distance herself from her then-human pal so that he wouldn't keep getting caught up in the fight. 

"I sat at your bedside for weeks, fearing the worst. I confronted something I had never confronted before: mortality. The finality of death in your kind," she explains. "You asked me once what a regular life would look like for you. I saw a vision of how it could be, for you to be free. It was extraordinary. You deserve to have something real to hold onto. That's why I left." It was only when Maeve tried to "reach out" to Caleb and his family seven years later that Hale managed to track them both down.

Elsewhere in 'Generation Loss', we see Bernard (Jeffrey Wright), Stubbs (Luke Hemsworth), and Frankie (Aurora Perrineau) digging somewhere in the desert – which is quickly revealed to be the Delos construction site where Maeve and Caleb died. "I'm sorry, C," Bernard says, as he uncovers a body. "It's not your father's. Caleb isn't here but the weapon I promised you is." It's Maeve, the weapon is Maeve. Might she be able to win the war, as Bernard has prophesised?

Fortunately, we won't have to wait too much longer to find out. New episodes of Westworld season 4 arrive on HBO and HBO Max every Sunday, following a day later in the UK on Sky Atlantic and NOW TV. In the meantime, fill out your watch list with our picks of the best new TV shows coming our way, this year and beyond.