Let's go over what we learned throughout the hour:
MEREDITH USED TO BE A COMPANY AGENT... Claire's birth mom was captured by The Company, along with her brother, Flint. (Yup, these two are brother and sister.) At first, Meredith was actually a decent agent, helping her partner capture an evil man with powers. But when she discovered that The Company was manipulating her brother, she escaped with him.
They were eventually tracked down inside the car of a train, as Flint escaped, yet Meredith was apprehended again. In the course of a discussion, it was revealed that Meredith thought The Company killed her daughter, Claire. The agent felt badly about this and actually let Meredith go. It was very nice to see a bit of Meredith's background, as her rise to agent status this season had seemed sudden prior to this flashback.
ELLE CRUSHED ON SYLAR... Elle was an agent back in the day, working with HRG. Their mission? To get close to Sylar, force him to kill/use his abilities and observe it for study. This was accomplished via Elle cozying up to the man still known as Gabriel, as she first walks into his watch shop when he's actually trying to commit suicide. Turns out Gabriel felt awful about the first men he ever murdered. But Elle puts a stop to the hanging attempt and grows close to Sylar.
She's torn about forcing him to kill again, but HRG insists this is their mission. He threatens to leave Elle alone in the city. As a result, she dos end up bringing another man with abilities to Gabriel and he cannot help himself: he opens up this man's brain and Sylar is officially born. Elle feels terrible about it, as The Company essentially played a role in creating the monster of Sylar. But HRG says it had to be done and they will capture him soon anyway (shows what he knew!)
ANGELA KILLED ARTHUR... Or at least she tried to. Angela learns that her husband intends on murdering Nathan because he's pursuing legal action against Linderman and this might expose all of Arthur's secrets (remember the very first episode of Heroes?). Therefore, Angela poisons Arthur's soup and he is pronounced dead at the hospital of a heart attack. But the doctor that makes the diagnosis?
He's the same doctor we see at Pinehearst later on, brain washed by Arthur. In this instance, we learn that the Arthur is paralyzed from the poison, but can still communicate - and control - with his mind. He forces the doctor to lie to Angela and finds another body for the Petrellis to cremate. As we know now, Arthur is very much alive and finds a way to come back to life fully.
Hiro sees all this via his spirit walk and says he and Ando must go warn Angela that Arthur is alive. But here's how the episode ends: with Arthur somehow appearing in Africa and saying to Hiro: "I hear you've been dreaming about me." Uh-oh!
Source: TV Fanatic