Definitely shouldn't be happy about the second one...
Anyway, here's a theory I found. Lemme know what you think:
I think that a lot of us have forgotten what Tartarus originally is. Tartarus doesn’t exist for the landscape, guys. It’s a prison. That’s why people like Tantalus and Kronos are sent there. And look at how similar Percy and Annabeth’s clothes are in the cover art- like uniforms. And a lot of people have pointing out how they’re running away from something, right?
What if Percy and Annabeth are escaping from Tartarus. What if they accidentally lead a godsdamned jailbreak?