I really wanted to wait until the end of the story to post a review, but it just can't wait. Avril, as a character, is really bad. She's the definition of a Mary Sue when it comes to Pokemon. Give her some flaws or something. Not just one flaw, but a human amount of flaws. Make you're character a believable human being. She's a young, beautiful girl. She has a bag full of level 1,000,000 Pokemon. She knows just about everything, everyone loves her, and she is even 'special' because she's the guardian of Articuno. Even James is risking his life after just meeting her. Jessie and James (believe it or not) have been best friends for years, and I'm pretty sure it took more than a few minutes for them to like each other enough to risk their own lives for each other.
Even if James betrayed Team Rocket, I seriously doubt Jessie and Meowth would turn on him like that. If anything, he would support him or even try to convince Giovanni that he's not a traitor. They might not look like the best of friends, but, beyond the three of them, they have no other friends.
Also, you might want to use spell check. You might think you don't need it, but trust me, you're going to need it. Even he most skilled of writers use spell check because every chapter is layered with spelling mistakes.
Also, don't post a chapter or story the moment you finish writing it. Re read it and see if it's up to you're standards. It helps to wait twenty four hours after writing the chapter to read it again. If o do that, ou can check for grammer mistakes, see if the story's pace is too fast, or see if the chapter feels awkward in a way.
If you want to set your standards high, you should read a really bad story that you or someone else has done, and then read a well written story.
Also, give your sorry the element of surprise. It's very predictable that James is going to start traveling or living with Avril. Then eventually, he will fall in love with her. Then they'll on this epic quest to stop Team Rocket. It's just all so predictable.
I'm not trying to be mean or a know it all. I just want to help you improve on your writing skills so no one else does it in a horribly mean way, and by mean, I mean bitch to the infinite power mean.

WOW! From bad guy to meeting Acrues! AWESOME! :) I cant think of any ideas tonight though.

Interesting...

Man, that was a LOT! Ggreat job! You did a great job with detail too and you really explained everything! :)

Awesome start!

this sounds interesting.

Nice chapter!

Wow, this story is super amazing!

Cool, I think James is a good character and this is an interesting direction you've taken with him. Him being so spunky and mischievous, I wonder how this experience will change him. You've opened the story with a lot of questions going through the reader's head, so I hope that a few hints will be given as the story progresses while still keeping the suspense lasting. I would go through and check for run-on sentences along with spelling mishaps. Also, blue-haired needs to be hyphenated. Other than that, I think you're good with conventions. I would love to see more descriptions of how it feels to be there in the snow and what the scene looks like. Bring the scene alive, lure the reader into it. Tell us how his teeth were chattering and the cold was biting at him he couldn't see two feet in front of him for all the snow flurries. (Or whatever you had in mind!) I mean, you do have some imagery, but I want more - this is such an intense scene and it's great if we can really feel what he's feeling. Oh, and sentence fluency! Try to balance the longer sentences with shorter ones a little more, I think that will help. Lastly, I like your little cliffhanger at the end - how is this mysterious girl going to figure into this? Keep it up!