Please remember this is meant to be a VR prison that you're not meant to be escaping from. In that vein, the narrative for the first part is fairly obvious. You break into the tomb, steal the necklace, and your reward is to end up her maid.
It has to be noted that it's probably not coincidental that the way you're secured by the goddess is near identical to how the real version of the player is secured. If you end up with the ending where you're sealed away in the tomb, again, it's the 'intended' outcome, in that, in both realms, you're identically secured.
