Ace Combat: Two Worlds is the 18th entry in the Ace Combat franchise. It released on the PlayStation 5 and the Xbox Series X/S worldwide on March 10, 2023. The game released on the Steam platform on March 21, 2023. Pre-order bonuses for the game included high-definition remakes of Air Combat and Ace Combat 2, bundled as Ace Combat: Phoenix; this game was later released separately on June 30, 2024.
The game's single-player campaign takes place during the Portal incident of 2025, in which an alternate Strangereal and the real world accidentally cross over due to mysterious circumstances. As both worlds begin to connect, high-profile incidents occur that threaten to sever their ties and pit the two against each other. Players control two characters: Scythe, a Yuktobanian Air Force pilot assigned to Klinok Squadron; and Blackberry, a British Royal Navy aviator assigned to the United Nations' D-4 Squadron. The game's story is told through cutscenes between missions, revolving around several characters from both worlds, namely Markus Denbe, an Osean intelligence officer working for the IUN; Frederick Solo, a Belkan soldier assigned to help maintain relations with the real world; and Janit Morowe, a U.S. Marine stuck in Guam.
The game's multiplayer is comprised of four player-versus-player modes—Team Deathmatch, Battle Royal, Hard Target, and Attrition—as well as two co-operative modes, Air Raid and Attack Scramble. Two Worlds also features a VR Mode, added in a DLC released on October 30, 2023 due to time constraints preventing its full implementation at launch. VR Mode focuses on Grendel Squadron from Ace Combat: Northern Wings as they are secretly deployed during the Emmeria-Estovakia War, Lighthouse War, and Aurelian War to eliminate possible threats to Nordennavic.
The game received favorable reception from fans and critics alike, who lauded the setting, single-player campaign, graphics, music, and multiplayer, but criticized the difficulty and confusing plot.
On August 2, 2024, IUN-PKF fighters pursue unidentified bombers over the Verusean continent. The bombers, attempting to evade their pursuers, fly into a massive storm in the Tolomek Bay, and the pursuing IUN fighters follow it in. The IUN AWACS reports the bombers and fighters have vanished from radar, and calls for assistance, believing them to have been destroyed.
Meanwhile, on the same day in the real world, a coalition naval fleet led by the United States deploys to the Philippine Sea to counter an opposing Chinese fleet. As the coalition prepares for possible war, Russian mercenaries arrive and order both sides to disperse in an attempt to rescue a convoy of stricken Russian merchant vessels between the two. As the situation escalates, multiple unknown bombers—the same from before—arrive from the east and begin indiscriminately attacking all sides. Blackberry takes off from the HMS Dublin aircraft carrier as the bombers destroy it, being the only fighter from it able to do so. As the IUN fighters also appear in the skies, the coalition, Chinese, and Russian forces, believing them all to be hostile, form an uneasy truce; Blackberry, along with Canadian pilot Jackie Gore, Japanese pilot Ai Takenoko, Chinese pilot Wu Wai-Lin, and Russian mercenary Dimitri Iliya, deploy and manage to shoot down most of the aircraft until an IUN pilot, Safir Muhanara, enters their radio channel and surrenders on behalf of the remaining IUN forces.
As the global situation deescalates, and the shot-down pilots are rescued and detained, the United States Navy manages to locate their origin as a large, seemingly perpetual storm, named The Portal, that is above Guam and has prevented anyone from leaving the island, including the U.S. Marine Corps 9th Battalion, which initially deployed to stop a possible rebel threat and is now stuck on the island, and of which Janit Morowe is a member. The United Nations establishes the United Nations Other-World Force to secure the area and attempt contact; this is eventually successful when a peaceful IUN mission emerges from the storm. Peaceful contact is made and relations improve strongly as official diplomatic links are made between the real world. Several discoveries, such as increased fuel efficiency for aircraft, mass drivers, and functioning laser weapon systems are shared with the real world, which mostly drops or resolves their current disputes to focus on the new world, named "Strangereal" from the UN Secretary-General's speech on first contact.
Eventually, the first flight from the real world to Strangereal is made, carrying numerous heads of state and being escorted by IUN-PKF and UNOWF fighters, including Scythe and Andre Bernitz, Scythe's wingman. Several unidentified fighters arrive and attempt to destroy the plane, but they are routed and successfully pushed back by the combined force. The plane lands at Doquick Airport in Velere, where a powerful bomb suddenly detonates on the runway, destroying the plane and killing everyone on board. The blast also injures Frederick Solo, a Belkan soldier who was tasked with securing the airstrip; he is taken into custody due to suspicions over his Belkan heritage. A terrorist group, the Universal Stabilization Front, claims responsibility and threatens to commit similar acts; however, their message sparks outcry as they claim they are doing this on behalf of Strangereal nations, heightening tensions between the two worlds.
Scythe is deployed with the IUN to locate and destroy the USF before they can cause more harm. After several skirmishes with them, including an airstrike on their ground forces in Sotoa, a dogfight with their pilots over Ventello Island, and a combined ambush strike in eastern Denone, the IUN discovers they are located in the Skully Islands, and Scythe and Bernitz manage to destroy their headquarters. The flight back to base is suddenly ambushed by a squadron of several unknown advanced fighter aircraft that appear to be from real world air forces; only Scythe and Bernitz escape. Meanwhile, Solo is interrogated by Markus Denbe, an IUN intelligence officer; he attempts to coerce Solo into confessing, but Solo resists and is taken into solitary confinement. In the real world, the 9th Battalion is resupplied by UN delivery drones, and Morowe remarks on how she once had a dream where she drowned in the eye of a similar storm.
Blackberry, Gore, Takenoko. Wai-Lin, Iliya, and Muhanara—now making up D-4 Squadron—are ambushed during a patrol around Guam by what appear to be Osean Air Defense Force fighters; confused when more OADF fighters arrive and shoot down the others, D-4 Squadron shoots down all of them. Strangereal aircraft suddenly stop traveling through the Portal; with nothing happening for several months, the squadron is reassigned to eliminate fighter aircraft that are being operated by the Papanoa Cartel in Mexico and the Fas Alqital terrorist group in Iran, both of which get into destructive air battles with D-4 Squadron over Guadalajara and Dubai respectively. An investigation into how the aircraft were acquired reveals they were secretly exported by Osea and Erusea. With tensions between the two worlds increasing greatly, D-4 Squadron is called back to Guam. Meanwhile, Morowe and the 9th Battalion locate the rebels they were initially deployed to find; they are using Chinese equipment, which would have confirmed American beliefs and would have likely led to an intense escalation of the conflict seen earlier, had the Portal not interrupted it. The 9th Battalion is unsure of how to deal with the revelation, and eventually forms a shaky truce with the rebels to get off the island first. In Strangereal, Denbe visits Solo in his cell to inform him that everyone believes he is guilty, that the world needs a person to blame, and that him constantly resisting a statement of guilt will only make things worse. Solo continues to plead his innocence, and Denbe orders him to be transferred to Usea.
It is revealed that, due to negative public support in the real world, the IUN has officially "shut down" the Portal. The UNOWF turns back an IUN peace expedition using warning shots, which only worsens the situation in Strangereal. Eventually, during a patrol around the Portal, Scythe and Bernitz are attacked by UNOWF fighters; the fighters are repelled, but the IUN cuts diplomatic ties with the UN, and both sides begin preparing for war. Meanwhile, Solo's transport aircraft lands at an incorrect airfield and is ambushed by USF militants, who capture the IUN personnel on board, including Denbe, and force the convicts to join them. As he and the other convicts from the plane are ferried out, Solo notices several IUN members being released and armed by the USF. In the real world, the 9th Battalion manages to locate an old flying boat that the locals repaired that they can use to leave, but neither the 9th, the rebels, or the locals can agree on who should board it and who should be left behind for what could possibly be the rest of their lives; the locals begin to riot, and the rebels become hostile and flee.