Wow, this could be good... A story with plenty of conflict and drama, right? Your plot summary:
"[I]ts about Carly coming back to Seattle two years later realizing she forgot something not spencer not Sam but Freddie."
Are you going to write about a showdown between Sam and Carly? If Carly is making a play for Sam's boyfriend, then I'm sure the sparks will fly!!
Personally, I'd think Carly should be afraid for her safety, if she tried to link up with Freddie. Sam doesn't take betrayal well. Thus, I think your story would be perfect for some intense conflict: anger, hurt feelings, a destroyed friendship...
And all that before you get to the romance stuff, eh?
Interesting possibilities. I think it will be interesting to see how you write Carly. Be careful; you could inadvertently make her appear like one of the "mean girls" in school. You know the kind: self-centered and selfish.
When's your first chapter?