I really like the idea of the flash back to the Marauders' Hogwarts days. It's creative, and it makes the story a bit more sad in a way, to see the way their friendship had turned from something so great to a hate so strong.
The beginning scenes with Ron and Hermione to Peter sleeping probably needs some sort of transition. The beginning seems slightly out of place, as the main story is about Peter's attack while being with Ron. I recommend changing the introduction to something a bit more on the subject of Peter's attack, just so the story goes a bit smoother.
Bullied into switching his loyalty, Peter lay scared and alone disguised as the loyalist garden rat alive.
If I'm reading this correctly, I think that 'loyalist' should maybe be 'most loyal'. I'm not completely sure on this one, but If not, I know that it should be spelled 'loyalest'.
Also, don't forget to capitalize the first letter of each word in your title, excluding 'a'. Other than those things I really did like this. Overall you did a good job!
Author's Response: Thanks, I'm glad you like it. Well, I've had a look at it isn't 'loyalest' as that isn't a word but you may be correct about it being 'most loyal'. I see what you mean about the beginning though, it is a little sudden. I just wanted to give a glimpse of the time period it is set in at first. Thanks for your feddback! :)
I must say that I really liked the description and image you've created with Peter's POV. It is hard to like Peter because he's a traitor, but I found this one appealing to say the least.
I particularly liked this sentence:
He knew that voice. He might not have heard it for twelve years but he would never forget it.
You definitely stayed in character with Peter, and explained why he decided to betray the Marauders.
I don't have any nit-picks except that at first when you "flashbacked" it didn't appear to have much of a point, but you connected it nicely back to reality at the end.
mugglemathdor ~ Knight of the Turnip Table
Author's Response: Thanks! I'm glad you liked it- I am about to reply to your PM now. I admit the flashback doesn't appear to have much relevence but it was designed to show the friendship the Marauders had and also how heavy footed Sirius is. I'm glad you liked my portrayal of Peter :)
I really liked it. It seemed to kind of walk the line between funny and sad, if that makes any sense (it probably doesn't). But it was very good, and a good portrayal of Peter.
Author's Response: Thanks, it was my first attempt at following just Peter in detail. I thought there must be a heart in there somewhere. Glad you liked it :)
Stupid rat. He should die! But I loved the flashback. It showed the whole group dynamic. How could Peter betray his friends? His best friends! *sigh* The way you wrote this I love how Peter was dreaming of the flashback and was awoken by Sirius. *sigh* I think it's great.
Author's Response: Thanks, I'm glad you liked it! I didn't know if the flashback detracted from the rest of it so thanks for your feedback :)