The House of Hades Main goals

After reading the first 3 chapters I noticed that there are a series of tasks that needs to be accomplished in order to achieve one main goal.

Main Goal: to stop Gaea from rising and destroy the world.

Tasks: 

1) to save Percy and Annabeth from Tartarus

2) to ensure peace between the roman and Greek demigods

3) get Diocletions sceptor and use his power to raise the army of the dead

4) get to Epirus 

5) prepare for the battle against the giants 

I predict that parcy and Annabeth will be able to escape from the goddess of the night and hat mansion using the mist. I also think that Damsen will come back and help delay tarturaus to permit Percy and Annabeth to escape through the doors of death. I think that the rest of the crew on the Argo II will be awaiting Percy and Annabeth's arrival through the doors of death. I think that Octavian will end up attacking the Greeks. I also think that Reyna will just be able to get the statue of Athena back to camp Half Blood just in time to ensure peace between the demigods.