When Stable-Tech builds something, they build it to last. If only they had taken into account the effects of erosion. During a fierce thunderstorm the undersea stable, Stable 24, is washed out to sea and is just buoyant enough to float. It is now up to the newly appointed Overstallion, Gristle, and his assistant Posey to keep the stable afloat and out of harms way, but that is easier said than done in the eastern ocean of the Equestrian Wasteland. Survival will literally be sink or swim.
- Gristle: the newly appointed Overstallion of Stable 30. He is a smart, confident unicorn but is prone to bouts of stage freight and other anxieties. He is also in his own head a lot thinking to himself about the situation.
- Posey: the former assistant to the late Overmare of Sable 30 and current assistant to Gristle. She is a confident and organized mare. Gristle describes her as positively pink since she has a pink mane, a pink coat, and pink eyes. She likely has a slight crush on Gristle.
- Gristle's Mother
- Gristle's Father: Died before the story began
- Gristle's Grandmother
- Elderly Grey Unicorn: lead Gristle's Overstallion induction ceremony.
- Gundhoof: The late Overmare of Stable 30. She is the predecessor to Gristle. Her death was unexpected and may have been due to murder.
- Boltz: engineer and maintenance worker in Stable 30. Not a fan of Gristle's leadership.
- Inflow: engineer and maintenance worker in Stable 30. Outflow's twin.
- Outflow: engineer and maintenance worker in Stable 30. Inflow's twin.
- Pure Water: engineer and maintenance worker in Stable 30.
- Rigger Up: head engineer and maintenance worker for Stable 30.
- Dr. Marine Bio: The hydrophobic head researcher and a prodigy marine biologist. she has a paranoid notion that mutant zooplankton in the ocean water is out to get her.
- Health Heal: Stable 30's physican.
- Venus: Radio DJ for The Watery Wasteland.