That's A Fact

Nina is just a hunter. That's a Fact (Okay, she's a Winchester. There's that. She's also a witch (don't worry, she's nicer than Rowena)).

Her Dad is never grumpy. Never. That's a Fact. Until the anniversary of the defeat of Amara and him (and Uncle Sam-squatch) losing someone named Cas.

Nina doesn't know who Cas is, but her dad is sad about him.

She doesn't know who he is, but she's gonna find him.

That's a Fact.