If you don't find him... well... there are other cities where you can build a life... if you don't find him, Poseidonis will be gone. 
- — Vulko
Aquaman (Volume 4) #1 is an issue of the series Aquaman (Volume 4) with a cover date of December, 1991.
Synopsis for "A Small World Incident"
Submarines sent from the sovereign nation of Oumland attack the domed city of Poseidonis. Repeated bombardments prove significant enough to cause a crack in the city's great dome.
Meanwhile, Aquaman goes to Newport Beach, California, where he tries to help some people move a beached whale back into the ocean. Aquaman senses that the whale beached herself following the death of her calf. He grows concerned as the local sea life have been behaving more oddly with every passing day.
In Poseidonis, King Thesily calls for an emergency council session to discuss the Oumlandian invasion. Present are Lord Vulko and Minister F'ancha. The session is interrupted as Oumlandian shock troopers (wearing deep sea gear) pierce the dome. In Oumland, its prime minister meets with an out-of-costume Black Manta, who presses him to begin Act II of the strike.
The invasion of Atlantis becomes public knowledge, and representatives of the United Nations convene to discuss the crisis. A politician named Mister Mission wants to enlist the aid of the Justice League, but since their international charter has been revoked, they can not rely upon their assistance.
After spending a moment of reflection at Mercy Reef, Aquaman heads towards the twelve-mile disputed area between Atlantis and Oumland. He intercepts several Oumlandian submarines and incapacitates them. After interrogating one of the commanders, Aquaman discovers that Oumland's attacks against Poseidonis was actually a retaliatory strike. Aquaman heads towards the capital city to get some answers, but an Oumlandian torpedo destroys the city's dome. Aquaman and Vulko are both caught in the blast.
Appearing in "A Small World Incident"
Featured Characters:
Supporting Characters:
Antagonists:
- Prime Minister Stom (First appearance)
- Black Manta
Other Characters:
- Aquababy (Flashback only)
- David Shelby (a news broadcaster) (First appearance)
- Echson Krystal (First appearance)
- Harry Cocca (First appearance)
- Henry (Mister Mission's aide)
- Justice League International
- L'Par Krystal (First appearance)
- Mera (Flashback only)
- Minkis (First appearance)
- Richard (Minister Stom's aide)
- Richard Mission (an American politician) (First appearance)
- Tyrn Krystal (First appearance)
Locations:
- Atlantis
- California
- Newport Beach
- New York City
- Oumland (First appearance)
Vehicles:
- six Oumlandian nuclear submarines
Notes
- The release of this series coincides with the fiftieth anniversary of Aquaman.
- First appearance of Thesily, the king of Atlantis. Thesily's reign follows that of the inept leader Pletus, and began shortly after the giant jellyfish invasion chronicled in Aquaman (Volume 3). He will remain Atlantis' king throughout the remainder of this series and the first year's worth of issues of Aquaman (Volume 5).
- This issue reveals that Vulko is still alive after he had been reported killed in Aquaman (Volume 3) #1.
- The Justice League's international charter was revoked following the events of the "Breakdowns" affair in issues of Justice League International and Justice League Europe.
- Mister Mission's first name is not revealed until Aquaman (Volume 4) #8.
Trivia
- Atlantis has four religions. Vulko believes in none of them.