- This article is about an in-game mission. For the in-universe event, see Operation Gambit.
Lost Butterfly is the first Campaign mission of Ace Combat Infinity, not counting Test Flight. Players are formally introduced to Omega and Goodfellow and are then tasked to defend Tokyo from a UAV intrusion.
Goodfellow: All right. Time to start the briefing. We've got a new guy here today, but I'll have to cut the introductions short. My name's Goodfellow, and I'm your rep from the Arrows. As you know, Arrows is a mercenary force specializing in aerial warfare. Some people like to call us "pirates". I'd prefer they called us "privateers", at least. We are being employed by the UN Security Council, after all. Anyway, the UNSC's military staff committee just sent Arrows a request for deployment. It was originally going to be an escort mission for the UNF Pacific Fleet stationed in Tokyo Bay, but that's changed. We now have multiple unknown UAVs flying toward Area J4E... Japan's former capital of Tokyo. In other words, right here. The UAVs are likely armed. We need them downed before they reach city limits. This'll be the first sortie for the rookie here, TAC name "Reaper". Here's your emblem. Omega from the Bone-Arrow flight will be supporting you on this mission. Follow his instructions. I'll be expecting results, you hear? Dismissed.
The player is spawned south of Tokyo, and must await instructions from Omega and Goodfellow before proceeding. Once the first two UAVs show up, they are instructed to shoot them down. A third UAV will then spawn, and the player is instructed on the use of special weapons to assist in shooting it down.
Three more UAVs are then spawned, two of which introduce the player to the TGT (important target) mechanic. Goodfellow notes that these UAVs are equipped with weapons, and must be destroyed first. The player does not have to follow his instructions, but must note that, whenever TGT units are available, they are the units that the player must destroy to advance the mission. After the TGT UAVs are shot down, three more UAVs marked as TGTs will spawn.
Once the last wave of UAVs are shot down, the mission is completed.
An S rank on this mission requires completion in under 3 minutes. The player must simply aim to use the fastest of their available aircraft, and waste no time in shooting down the UAVs.
Goodfellow: This is believed to be a terrorist attack carried out by armed forces from the Iyuli region. They've caused extensive damage to Tokyo. The naval fleet was also attacked, so the UNF generals are all furious right now. The UAVs they used are an upgraded version of the MQ-90 Quox, a Japanese-made UAV that's also been deployed in the Americas. It may be unmanned, but it's still a very powerful bomber. It's equipped with an aggressive aerodynamic design and a new type of semi-automatic control system. The UNSC says it's a Wernher Noah product. Apparently the control system's a top-secret design that they stole. Wernher denies everything, of course. Navigation would normally use a system that relies on improved GPS satellite tech, but this craft uses a different relay system for its operations. We also caught an unknown fighter craft flying at high altitude over the area. The UN's going to raid and inspect Wernher's facilities in Iyuli and the other special zones shortly. Wernher Noah's the biggest company in its field. Normally the UN doesn't like doing anything to make them angry. Now, though, I guess they don't have much choice.
- The background music of the mission is "Sitting Duck" from the Ace Combat 04: Shattered Skies Original Soundtrack.
- If the player attacks the Bandai Namco Games Inc. Headquarters, Omega will shout at the player: "Whoa whoa whoa, you don't want to go there! Sheesh, you're crazy."
- If the player does not shoot down the third wave of UAVs within 45 seconds, Camilla will be heard on the radio humming the theme song of Mappy, during which Omega will comment on civilian radio noise. This confirms the "unknown fighter craft" that Goodfellow mentions in the debriefing is a QFA-44 Carmilla.
- If the player does not shoot down the fourth wave of UAVs within 60 seconds, Omega will comment that they "keep dodging our fire... they're like butterflies". This is a nod to the mission name, and becomes plot-important in Far Eastern Front - the MQ-90Ls protecting the QFA-44 are nicknamed "butterflies" by all of the pilots, and the QFA-44 itself (which has a butterfly emblem painted on it) the "Butterly Master". This also confirms that all of the UAVs in this mission are controlled by Camilla herself.
- If the player goes to the very north of the combat area, they can spot a light meteor shower taking place in the distance. Higher altitude may make it easier to spot.
- The S rank requirement for this mission is possibly the simplest of the Infinity missions, since there are so few enemy units.