Set in a spacefaring science fiction world, the plot follows the development of the protagonist Mia, who joins the crew of the maintenance ship Aktis and attempts to reconnect with a lost love.

The two girls become friends, getting closer after Mia fights a group of bullies to retrieve Grace's prized necklace that was stolen from her, and eventually fall in love.

The Staircase is not easily inhabited due to violent storms that threaten to erode the surface, but is also home to fantastical wildlife, hot springs and so-called "healing rock".

Grace was delivered to Cleary, despite protests from her family, thanks to Alma and Charlotte (nicknamed "Char"), a married couple and the crew of the ship Aktis, who illegally help those stranded on The Staircase cross the border.

Now, rock formations on The Staircase's exterior are forecasted to shift, blocking the only path to the interior, and the Hills want Grace to return immediately, or else risk never seeing her again.

Having graduated high schools with a poor academic record, she has few prospects and thus accepts a position on the Aktis, which has been reformed and now travels throughout the galaxy, restoring buildings scheduled for recycling.

The crew finds the Hills' surface-level house deserted, reasoning that the worsening storms must have necessitated a mass exodus to The Staircase's naturally-occurring caverns.

They descend to find an underground city and are intercepted by a patrol squadron, causing them to split up: An unspecified time later, Jules and Elliot have fully recovered from their respective injuries.

"[14] Rowan Hisayo Buchanan of The Atlantic noted that the resistance to viewing profit as an "ultimate goal" goes beyond the story itself to the way it was made, with the whole comic still "online even after the book deal," meaning it is "simultaneously free and available for purchase.