Arcadia is only strong as long as we are united, and A-Force is her defender. It's our honor and duty to protect our island and her people. And that's exactly what I mean to do. Summon the Sub-Mariners! Something has trespassed our borders, something that is a danger to all Arcadia. What it has set in motion, I cannot say. I do not know where or why that monster appeared -- but is cost us one of us. And more may be coming. Tonight, we are going to learn the truth. We are going to learn the source of the apparition that cost us our sister. I won't allow any others to suffer America's fate. We will find the threat. We will root it out. We will know at last -- for good or evil -- what serpents have come into our garden. 
Appearing in 1st story
Featured Characters:
- A-Force (First appearance)
- She-Hulk (Jen Walters) (First appearance)
- Loki (First appearance)
- Miss America (America Chavez) (Leaves)
- Sister Grimm (Nico Minoru) (First appearance)
- Dazzler (Alison Blaire) (First appearance)
- Captain Marvel (Carol Danvers) (First appearance)
- Medusa (Medusalith Amaquelin) (First appearance)
- Pixie (Megan Gwynn) (First appearance)
- Spider-Woman (Jessica Drew) (First appearance)
- Meggan Puceanu (First appearance)
- Crystal (Crystalia Amaquelin) (First appearance)
- Storm (Ororo Munroe) (First appearance)
- Phoenix (Jean Grey) (First appearance)
- Rogue (Anna Marie) (First appearance) (Cameo)
- Black Widow (Natasha Romanova) (First appearance) (Cameo)
- Spectrum (Monica Rambeau) (First appearance) (Cameo)
- Spider-Woman (Gwen Stacy) (First appearance) (Cameo)
Supporting Characters:
- Sub-Mariners (First appearance)
Antagonists:
Other Characters:
- Luke Cage (First appearance) (Cameo)
- Jessica Jones (First appearance) (Cameo)
- Danielle Cage (First appearance) (Cameo)
- Gambit (Remy LeBeau) (First appearance) (Cameo)
- Black Bolt (Blackagar Boltagon) (First appearance) (Cameo)
- Thor Corps
- Thor (Sam Wilson) (First appearance)
- King Thor
- Thor (Red Norvell) (First appearance)
- Stormbreaker Ray (Beta Ray Thor)
- Thunderstrike (Eric Masterson) (First appearance)
- An unidentified Thor (First appearance)
- Zombies of the Deadlands (Cameo)
- Sheriff Stephen Strange (Appears on screen)
- God Emperor Doom (Victor von Doom) (Mentioned)
- Singularity (First appearance) (Unnamed)
Races and Species:
- Humans
- Frost Giants
- Mutants
- Human-Kree Hybrids
- Inhumans
- Atlanteans
- Atlantean-Human Hybrids
- Megalodons
- Asgardians
- Korbinites
- Zombies (Cameo)
Locations:
- Earth-15513
- Battleworld
- Arcadia (First appearance)
- Hall of Justice (First appearance)
- Bishop Lighthouse (First appearance)
- The Shield
- Deadlands
- Arcadia (First appearance)
- Knowhere (First appearance) (Cameo)
- Battleworld
Items:
- Staff of One (First appearance)
- Mjolnirs
- Stormbreaker
- Thunderstrike (First appearance)
Synopsis for 1st story
An island nation stands alone, separated from the rest of Battleworld. Arcadia is considered a paradise, described by Baroness She-Hulk as "red roofs and friendly dogs, green hills and water blue as heartache". In Arcadia, their protectors are entirely female, and their task is to patrol the borders of their land.
While patrolling the docks, Meggan and Crystal discover an enormous Megalodon shark. They call in the day's strike team: Miss America, Nico Minoru, Dazzler, Captain Marvel, and Pixie. She-Hulk officially assembles the A-Force, and they take action against the Megalodon.
Captain Marvel knocks the shark back with an uppercut, but Miss America is grabbed by it. The shark then dives down, clutching America's hoodie in its jaws. Dazzler starts evacuating citizens, while Nico Minoru uses a bioenergy blast to stun the shark into releasing America. The shark, using the last of its energy to hurl itself out of the water, redirects the bioenergy blast at the evacuating civilians. Dazzler uses her powers to beach the Megalodon, and America throws the shark over Arcadia's walls. As the shark falls, it is revealed that the Arcadians are not aware they share their furthermost border with the Deadlands.
Falcon Thor comes and tells America Chavez that she has violated Battleworld's greatest laws: breaching The Shield and forsaking the sanctity of Doom's borders. America responds with sass, telling him to "take it easy, tall, dark and hawkward!" while Nico pleads for America's release, saying that everything will be okay.
Sheriff Strange speaks to She-Hulk as a hologram, saying that he has sentenced America to work on the Shield. Storm, Phoenix, Spider-Woman, Medusa, Captain Marvel, Pixie, She-Hulk, and others gather to say goodbye to America. Loki also arrives, and America gives her instructions for what to do while she's gone. The Thor Corps arrives, and they take America to the Shield. Nico and Loki lash out at She-Hulk, leaving the going-away gathering in a fit of rage.
She-Hulk, Spectrum, and the other members of the farewell gathering call on the Sub-Mariners to investigate the sudden appearance of the Megalodon. They dive down to explore the ocean, and Namorita discovers something with a shocked reaction.
Meanwhile, Nico sits at Bishop's Lighthouse, crying about her inability to save America. As she looks up at the sky, she sees a humanoid shape descending in a streak of blue light. The streak hits the ground in front of Nico, leaving a crater. Nico looks inside, and discovers a girl seemingly made of the night sky.
Solicit Synopsis
• Marvel’s Mightiest Women finally get their own explosive series!
• In a secluded corner of the Battleworld, an island nation is fiercely protected by a team of Avengers the likes of which has only ever been glimpsed before…
• Fighting to protect the small sliver of their world that’s left, the Amazing A-FORCE stands shoulder-to-shoulder, ready to take on the horde!Notes
- After being exiled to the Shield, Ms. America appears next in Siege (Vol. 2).