- This article is about an in-game mission. For the in-universe event, see Operation Vanguard.
- For the magazine, see FRONT LINE.
- "C'mon, Arkbird! Use your lasers! The nuggets are gonna get killed!"
- ― Kei Nagase
Briefing Officer: A large combined force of Yuktobanian vessels and aircraft has been detected advancing in the ocean directly toward Sand Island from the west. Our intelligence has confirmed the presence of amphibious assault ships within the oncoming fleet. We believe the enemy's goal is to conduct a landing operation on Sand Island and capture this base. Close with the enemy, disrupt landing operations and suppress their naval gunfire directed at our forces ashore.
Perrault: Even if this turns into a ground war, I am prepared to fight for this island to the bitter end. As my advance guard, I want you to forget everything else and concentrate on dealing a lethal blow to the incoming enemy invasion fleet. We'll be deploying everything we've got. Launch every aircraft capable of anti-ship combat, regardless of combat experience.
The player will spawn at the far east edge of the map, looking directly towards the invasion fleet coming from the west. Most ships (except missile boats) and all helicopters are marked as TGTs - if any TGT crosses the combat zone border to the east, the mission will fail. The player must destroy as many ships and helicopters as possible to prevent that from happening.
When four minutes have elapsed or the player destroys any 8 ships, whichever comes first, the Scinfaxi will fire a burst missile. The player is warned to raise altitude to 5,000 feet to avoid the detonation, but AWACS Thunderhead reports an unknown command override. When the countdown ends, a laser is shot from the orbiting Arkbird and the missile is vaporized. This laser can kill the player and will consistently appear close to the player's aircraft; it must be avoided at all costs.
With promised support from the Arkbird and an anti-submarine patrol plane, Blue Hound, the player is ordered to continue firing on the fleet. Enemy F/A-18Cs begin to spawn from the Scinfaxi and will also fire on the player, but the objective remains to keep the enemy ships from penetrating the eastern border.
After the Arkbird destroys another burst missile, the Scinfaxi starts to fire multiple missiles to combat the Arkbird's laser recharge time. One more burst missile is destroyed, but the one afterward is warned by Thunderhead with a countdown and successfully detonates; the player must avoid this and all subsequent burst missiles (alerted by Thunderhead) for the remainder of the mission.
After an unknown trigger is completed, the Arkbird will fire a laser into the water to damage the Scinfaxi and force it to surface. After a cutscene, all enemy forces disappear and are replaced by the Scinfaxi, which now must be destroyed. The submarine is armed with numerous SAMs and Anti-air guns, and it will repeatedly launch F-35Cs to engage the player. Burst missiles will also continue to be fired, until the launcher port is destroyed.
When the two TGTs - the launcher port and the main submarine body - are destroyed, the Arkbird will fire one last laser at the Scinfaxi, creating a hole in the submarine and preventing any new aircraft from spawning. The player must attack the hole until the submarine is fully destroyed. Once this is done, the mission is completed.
Achieving an S Rank on this mission requires earning 17,000 points or more by the end of the mission. It's simple to earn, given the plethora of enemy ships and aircraft to shoot down. If the player has already made it to the Mission Update and is still missing a lot of points, it's advised to destroy as many aircraft as possible and avoid firing on the specific TGT named "Scinfaxi", as destroying this will prevent new aircraft from spawning.
Briefing Officer: The Arkbird was successfully employed over the forward edge of the battle area. The enemy amphibious force attacking Sand Island was repelled, and their invasion plans halted. The underwater carrier Scinfaxi, a lethal enemy threat, was engaged and destroyed by the superior firepower of the Arkbird. Having lost the support of the Scinfaxi, the remaining Yuktobanian forces retreated. Furthermore, we are requesting reinforcements from Central Command to replace our squadron members lost in combat.
- This mission is one of the only times in the Ace Combat series where the player has to defend a shoreline from an incoming landing operation. To add to the irony, this mission takes place in broad daylight as opposed to missions such as Lit Fuse later on, or Operation Bunker Shot in Ace Combat 04: Shattered Skies, both of which take place during stormy weather.
- Two Yuke soldiers even allude to this in the mission: << Great weather. I can see for miles around. >> << Perfect weather for a landing, eh? >>
- Despite the briefing showing eight allied F-5Es accompanying Wardog, only three appear in-game.