Unexpectedly found nil while unwrapping an Optional value while opening UIViewController

I'm doing a simple tableview app with swift, in which you open a new view controller programatically after clicking on a table row:

class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

//GLobals
@IBOutlet weak var table: UITableView!
//Table View Data

let cats :[String] = ["Gala","Vito","Odin","Ema"]

override func viewDidLoad() {
    super.viewDidLoad()

    table.delegate = self
    table.dataSource = self
}

// MARK:  UITextFieldDelegate Methods
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
    return 1
}

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return cats.count
}

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = table.dequeueReusableCellWithIdentifier("CustomTextCell", forIndexPath: indexPath) as! UITableViewCell

    let row = indexPath.row
    cell.textLabel?.text = cats[row]

    return cell
}

func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    tableView.deselectRowAtIndexPath(indexPath, animated: true)

    let row = indexPath.row
    let cat : String = cats[row];
    println(cat)

    //Save cat for detail view
    var defaults = NSUserDefaults.standardUserDefaults()
    defaults.setObject(cat, forKey: "cat")
    defaults.synchronize()


    let detail:Detail = Detail();
    self.presentViewController(detail, animated: true, completion: nil);
}
}

The code in the detail view is the following:

class Detail: UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()
    self.view.backgroundColor = UIColor.whiteColor()

    let defeaults = NSUserDefaults.standardUserDefaults()

    let cat = defeaults.stringForKey("cat")

    var label = UILabel(frame: CGRectMake(0, 0, 200, 21))
    label.center = CGPointMake(160, 284)
    label.textAlignment = NSTextAlignment.Center
    label.text = cat

    self.view.addSubview(label)
}

override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
    let home:ViewController = ViewController()
    self.presentViewController(home, animated: true, completion: nil)
}

However when the app goes back to ViewController I'm having "unexpectedly found nil while unwrapping an Optional value "

I have try some of the other answers to this problem including, warping with if == nil some of the values, but I still can't find what is the problem.

I'm assuming the UIViewController is not loading the UITableViewDelegate and UITableViewDataSource again, but I don't understand why... and how would you load them from another view anyway?