Kaldheim. It's going to have Snow. And Vikings.

[rufus]

Why doesn't "Creature cards in your hand have morph. Their morph cost is equal to their CMC" fit the rules?

There's no rules problem per se, but it doesn't do what it ought to. I'm not 100% sure you'd be able to cast it face-down and once the card is face-down on the battlefield it's a new object and it's not in hand, so it doesn't have a morph ability that allows players to flip it face-up.