In order of the most interesting storylines I would place Tracy's first, the company's second, Hiro's third, Claire's fourth and Mohinder's last.
Tracy's was the most interesting because, firstly, I found myself wondering who the hell this girl actually was, ('Is it Nikki? Nikki's split personality Jessica going by a new name? Or perhaps the witchy Gina?) which is always fun. Secondly Tracy displays an incredible power, freezing, similar to one of Sylar's many abilities which he lost in season 2, due to the effects of the Shanti virus.
The scene where she freezes the skanky reporter was amazing (the whole episode was worth watching just for that). With this character and her power, we will hopefully be able to witness many more of Tracy's ice attacks, which, so far, has been one of the greatest effects ever achieved on Heroes.
Next up there is Sylar's attack on the company.
The best thing about this storyline was that the great Kristen Bell made a brief appearance as Elle, and also that amazing ability of hers… Elle's character is the most human, I find, with a very interesting back-story that explains why she is the way she is. Let's hope that she returns later on in the series, she's such a great character.
After killing Elle's father, Sylar attacks Noah and then tries to steal Elle's ability; the pain sends Elle's ability spiralling out of control, unleashing a powerful electrical shockwave knocking out Sylar and disabling the power grid on Level 5, letting the villains loose…
The whole of this scene was very short, quick and snappy.This is what made it work so well, less is more. The whole sequence lasted for no less than a couple of minutes, in which I was transfixed to the screen.
After Elle releases a burst of electricity, the camera pans to a dramatic close up of her face, full of panic and confusion, Elle looks helplessly on as the Villains flee, the alarm booming in her ears…This scene was superbly acted and atmospheric, setting the events for the main story ark of Volume 3 in motion.
A couple of moments later we are in Paris with Ando and Hiro. As usual their storyline was fun and full of great humour, providing us with a more relaxing, lighthearted story amidst all the chaos of this episode.
Meanwhile, Claire has dicovered that she can't feel pain after her attack, allowing us to have a snippet of that brilliant Shankar, in a scene where Claire emotionally declares to Sandra that 'pain was the only thing that made her feel human'. This extent of her ability is an interesting development, opening many doors for her character, who can now do almost anything…and let's not forget the most welcomed return of Meredith. It was a great disappointment that we only got to see Claire's Biological Mother for only two episodes in Season 1, she was such a intriguing character. Bringing her back was a great decision.
Lastly we come to the least entertaining story, Mohinder's, in which he begins to mutate. Hmmm…remind you of anything, a crazy scientist tries out his latest invention and his skin starts to drop off…this a complete rip off of 'The Fly' and is painfully ridiculous.
Well, all things considered, 'The Butterfly Effect' has been a very good episode, apart from Mohinder's obscene storyline. This, however, is the one and only bad side of 'The Butterfly Effect'.