IPhone : Reading data from NSUserDefaults

I write game on Swift in SpriteKit. I have two classes one is named "GameScene" and "PlyScene". I want to read highscore from "PlyScene" in "GameScene" class, but when I do it I have Thread 1:EXC_BREAKPOINT

Cod in PlyScene:

 func save() -> Int{

    if score2 < score{
    score2 = score
    println(score2)
    let defaults = NSUserDefaults.standardUserDefaults()
    defaults.setObject(score2, forKey: "score2")
    defaults.synchronize()

    }
    return 0
}

Code in GameScene:

 let defaults = NSUserDefaults.standardUserDefaults()
    if let score: AnyObject = defaults.valueForKey("score2"){
        println("yes")
        scoreText1.text = String(score as NSString)