- This article is about an in-game mission. For the in-universe event, see Operation Long Harpoon.
- "Hrimfaxi, it appears you're up against Razgriz itself out there."
- ― Yuktobanian command officer
Perrault : Ahem, gentlemen...
Mitchell: Excuse me Colonel. This is an absolutely vital mission to us. As the staff advisor sent from Central HQ for this effort, I'd like to explain it myself. The Osean Army is planning a vast offensive with the ultimate objective of occupying the capital of Yuktobania. If this operation succeeds, it will end the war in very short order. However, the Yuktobanians have attacked our beachhead with ballistic missiles from the Hrimfaxi, a Scinfaxi-class submersible carrier stationed in the icy waters of Razgriz Straits. Fortunately, our ground forces have already completed attack preparations, so despite the missile attack, the offensive began as planned. Nevertheless, we must neutralise the threat of another Hrimfaxi missile attack on our ground forces.
Briefing Officer: We have a single chance to stage a successful air attack on the underwater carrier Hrimfaxi. Our passive sonar has detected a transport submarine that we believe is headed for the Hrimfaxi. We believe the transport sub's mission is to supply the Hrimfaxi with missiles. Based on its course and speed, we've calculated its rendezvous time with the Hrimfaxi. By amazing coincidence, it is precisely the same time as the zero hour of our ground attack. At this time, the Hrimfaxi will have to surface to restock its missiles. At that exact moment, ingress at low altitude to avoid detection, launch a surprise attack, and sink the Hrimfaxi. Once surfaced, it only takes the Hrimfaxi one minute to rig for an emergency dive. If your approach is detected, you will only have one minute to complete your attack on the Hrimfaxi.
Mitchell: Now, keep in mind there won't be any support from Arkbird this time around. This mission rests solely on your shoulders. The entire ground offensive is relying on this first surprise attack, so don't disappoint us. I want you to turn the icy Razgriz Straits into the enemy's graveyard.
The primary objective of the mission is to sink the Hrimfaxi. The player must approach the Hrimfaxi while remaining under 1,000 feet to avoid radar detection. The player will be detected if they fly above 1,000 feet, fly near a picket submarine or attack a picket submarine. Once the player is detected, the Hrimfaxi will begin to prepare for an emergency dive, allowing only one minute to reach it and attack it.
Once damaged, the Hrimfaxi will surface to attack the Osean ground forces with burst missiles and attack the player with UCAVs, AA guns and SAMs. The player must sink the Hrimfaxi before the Osean ground forces are driven back. The mission ends when the Hrimfaxi is sunk.
The surprise attack on the Hrimfaxi was a success, and the carrier has sunk to the bottom of the Razgriz Straits. The threat from the northern sea has disappeared, and the Osean forces are on the offensive against Yuktobania.
- If the player chooses to fly an aircraft with long-range air-to-ground weapon (such as the F-2A) and uses SP weaponry to sink the first sub encountered in the mission, they'll be netted with an special response from Chopper. However, the loss of the submarine alerts all other ships in the area, and thus the mission proceeds as normal.
- If the players flies at 7,000 feet or higher once the Hrimfaxi submerges, they will be able to see the carrier as though it was on the surface.
- There are hard to spot polar bears on the surface.
- This is the first time the Anean continent is seen in the Ace Combat series.