The first chapter. It opens up with citizens of Vault 20 heading to a special event, from the perspective of a young man named David Mordin. He and his wife are talking excitedly about what a wonderful day this is as they wait for it to start. Unfortunately for them, the event was releasing Alex Mercer into their vault, and the first thing he does is shriek, leap, and slaughter them all.
Honestly, Alex in general, as per usual. He's still the unstoppable, shapeshifting, human-eating, viral abomination he was in [PROTOTYPE], but now he's in a setting where people are even less equipped to deal with him. Even when he isn't trying to be scary, he still is—his Icy Blue Eyes are way too piercing to be human, and at one point Cain mentions that the sounds when he eats are going to give her nightmares.
A string of bad luck during their adventures leaves Alex dropping lower and lower in biomass, and growing hungrier and hungrier. And the only people around are his two companions… At the lowest moment, he’s actually reciting to himself NOT to eat them, and practically throws Cain into a wall trying to get her away from him before he does. The thought that you might lose control and accidentally eat your companions is singularly terrifying.
It’s also terrifying from their point of view. Learning that your travelling companion is a superpowered viral monstrosity is surprising, but Cain and Arcade take it in stride. Learning that your travelling companion also devours people, and was moments away from devouring you? And that said companion is both far deadlier and faster than you? And that you are currently alone in the middle of nowhere with said companion?
Upon absorbing a deathclaw, Alex discovers it has chameleon DNA, and promptly tacks it onto his skillset. Alex can now turn invisible, on top of everything else.
During their infiltration of the White Glove society, Cain has a moment of realizing that they kidnap people from Freeside...and Arcade used to walk around there alone at night. He could have been snatched off the street and eaten by cannibals.
After Cain spills some of the beans on what Alex is to Veronica, he drags her away from her bedroll to ask her what she was thinking. We get a mention in the next chapter of how Cain was sure for a minute that Mercer had lost it and was about to eat her.
The explosive collars are terrifying enough in the game. Now you get to read Cain’s panic and fear when she realizes just what is around her neck, and how she has absolutely no control over whether it goes off or not. In the game, the companions will just wait for you, but as far as she knows, they could be getting themselves killed and taking her with them, and she can’t do anything to stop it.
The Cloud. Not just is the literal air poisoned, Elijah says it has infected everything, including the water, and then goes into lovely detail about what prolonged exposure will do to you. In short: corrode you from the inside out. And it can also burn away Alex's biomass. Now remember that Cain is trapped in that stuff, and after a while, she picks up a cough that just won’t go away...
Speaking of the Cloud, that’s the light version. The congested version is so poisonous, it will kill you in seconds.
And of course, there are bear traps and landmines everywhere, so Cain can't just run through the Madre to decrease her time in the Cloud. Nope, she's got to double-check every step she takes, lest she wants to end up minus a leg or blown to pieces.
Ghost People. They move wrong, they bleed wrong, and they’re hard to kill—one gives Cain a near-deadly Jump Scare by leaping at her when she thought she’d killed it. And when Alex tries to eat one? It makes him explode and melt at the same time, creating deep, oozing holes in his body and boils that rupture goo. Ewww, and ahhh!
Christine's introduction, as usual. Alex and Cain find her trapped in the malfunctioning Auto-Doc, and rescue her to see that her vocal chords were torn out. It doesn't take them long to realize someone did it on purpose. In fact, this trope is straight-up invoked In-Universe, with Cain particularly horrified at the possibility of being trapped and voiceless.
Dog. His introduction rings of Mood-Swinger, with him going from cowering in lost misery to perking up at the thought of eating Alex and back again in a few minutes. He's almost like a little kid, except he's an eight-foot-tall Nightkin who reminisces at the thought of chasing food, in this case people. It's equally disturbing as it is sad.
When the Sierra Madre crew manage to bargain a few hours of rest out of Elijah, Alex takes watch. A throwaway line has him liken the Cloud to how the sky burned in Manhattan in his earliest memories. Alex may be a viral abomination, but he's clearly unsettled by the Sierra Madre as well.
Alex manages to bring a bit of horror to this as well - at one point, Cain accidentally bloodies her own nose and leaves drips and spots of blood on the floor. She looks back to see Alex kneeling over it, his feeder tendrils scooping it up off the ground because he's that low on biomass.
In Chapter 38, while fighting off Ghost People, the shockwaves from some of Alex's tasks blow the Cloud around—engulfing Cain. It's only for a brief moment before Alex gets her out, but his description of what she looks like is horrifying; third-degree burns, blood dribbling from her ears, and skin sloughing off. When he sets her down to treat her, bits of her flesh actually peel off and stick to him.
Down in the Sierra Madre's vault, Alex comes within a hairsbreadth of eating Cain. As in, starts scraping bits off of her because his Horror Hunger has gotten so bad.
After Elijah finally dies at Alex's hands, Cain's collar starts spinning up to go off, and the elevator isn't going to move fast enough to get them out of range. Alex forms himself into armor around Cain, tanking the explosion for her, but as he doesn't have time to explain to her what he's doing, she sincerely thinks he's eating her alive while he's doing it, then starts flashing back to being buried alive.
While Cain and Alex are at the Sierra Madre, Veronica and the Brotherhood of Steel have figured out who - and what - Alex is. If and when they get back to the Brotherhood's bunker, things are not going to go well. Doubly so now that Veronica - the only peacekeeping element they might have had between them and the Brotherhood - fled the bunker and is on the run.
