This chapter picks up after the events of Fathom Vol. 1, diving deeper into the underwater world and the political intrigue surrounding the mysterious aquatic race known as The Blue.

In "Poseidon Shrugged," tensions rise both on the surface and beneath the sea. Aspen Matthews, the series' protagonist, is grappling with her dual identity—part human, part member of The Blue—while the world faces new threats from technology, corruption, and hidden agendas.

The title "Poseidon Shrugged" plays on Ayn Rand’s Atlas Shrugged, hinting at a power struggle among those who control the oceans, with elements of rebellion, moral conflict, and personal identity.