The telling of how the story began, of how Quint dooms the world, and then begins on the quest to save it. All stories must have a beginning, this is but one beginning to one story.
The protagonist/you are an Octonaut. Everything was doing well until things weren't the same anymore. Something had changed. The protagonist/you are on a infectious discovery trying to figure out what is going on.
(It's an AU from my childhood ACK ACK)