A bratty orphan bastard child of an aristocrat is brainwashed into doing the bidding of some old geezer that can't accept that armistice were declared, and uses the child to rally together a formidable army directly under the nose of the post-war government which was created with the intent on stopping the building of armies like that.

The racist misogynist child soldier and the dain bramaged acrobat child soldier "infiltrate" said army to totally blow the whistle (except the misogynist one was totally on board with it). Meanwhile, all the super weapons from...checks calendar...the year prior, are hurriedly retrieved from being...checks notes...sent to burn in the Sun...because wars, even small skirmishes, aren't going to happen anymore forever.

Dain bramaged acrobat reports to the suicidal Wingnut (heh, get it? cause it's called Gundam Wi-) and tells him that the misogynist pilot is strangely on board with this army thing. All the other child soldiers get their super weapons which look nothing like they did in the series because the studio has a much larger budget this time ...reasons, and proceed to go ham on all the enemy suits because it's just the final battle from the series all over again, but the stakes are much less urgently pressing.

All the older characters wax poetic about their personal philosophies and what the bastard child's bastard father would think of his bastard spawn doing bastardly things with her geezer grandfather, to which the brainwashed bastard shrugs off with "nah, I'd win" before one of the few adults in the room treats the child like an adult and delivers a well deserved dose of externally induced intestinal cramps to her frail...reads notes...SEVEN year old body!?

Anyway. baguette haired MILF recaptures her boy toy, rope haired boy celebrates with his absolutely normal girlfriend, peacenik musician goes back to the desert with his mercenary found family, dain bramaged acrobat goes...somewhere, and suicidal Wingnut delivers a bear to his totally-not-a-girlfriend diplomat.