This involves a bit of guesswork, since Indy 5 won’t be out for a while.
Indy arrives in Vietnam. To better establish the time and place, he has to sneak past the US forces there during the war. They’re largely demoralized, because the end of the war is nigh, and they’re not winning it. He manages to cross over into Vietcong territory, and is able to rent a room for the night.
In a call-back to the assassination attempt in Temple of Doom, Indy is attacked in bed. But 40 years have passed; and he doesn’t even stir as the assassin creeps in. We milk a little comedy out of it as Indy loudly saws logs as the assassin prepares to deliver a killing blow. He’s attacked instead by Short Round (Wan Li), the now adult (and incredibly bad-ass) Ke Huy Quan, who, no, really, is a stunt coordinator and an expert in Taekwondo (and very excellent in Everything Everywhere All At Once). Indy’s startled by the fight; Harrison Ford does a good befuddled face, and we could use one of those as he’s at first confused, then puts out a leg to trip the bad guy to help Short Round win.
“You sleep a lot sounder than you used to,” Short Round says, giving Indy a hand up.
“I got old, kid.”
This Indy is retired. He’s getting the band back together (basically calling back in any surviving cast for a Legasequel) to try and rescue his dumbass son. His son has become a tomb raider; he thinks he’s carrying on his father’s legacy, but he’s actually at this point the black sheep (which only makes him feel more like the Indy to his dad’s Henry Jones).
Indy’s in Vietnam because that’s where Mutt is. Some like-minded tomb raiders are using the fighting as cover to raid archeological sites- specifically, the Hanoi citadel destroyed by the French, and incorporating sections as old as 1400 years. In case any of this sounds familiar, I am indeed suggesting they’re raiding one of the citadels eventually officially excavated by the Vietnamese government in 2003. After a disagreement, Mutt’s being held captive, possibly for ransom though the note’s unclear on that point.
Depending on how we’re doing for time, and how many veterans are returning, we might have to montage it, but Indy and Short Round gather/rescue all of their players, and help smuggle them to Hanoi. I’m assuming their cover is that they’re there as Russians, potentially there to provide aid and assistance. We could get some really poignant moments out of this; Short Round’s actor is Vietnamese American, so the destruction would likely hit close to home for him.
Indy and company fight their way inside the camp purportedly holding Mutt captive… only for Mutt to stumble out of his tent, clearly free and also confused. That’s when our real villain reveals himself. He’s Mutt’s quasi-mentor in this endeavor, and because he’d be a great and fun choice, and because he’s expressed conceptual interest, I’m just going to assume he’s being played by Mark Hamill, and we’ll call his character that. He sent the letter to Indy, because his son just isn’t the genuine article. He’s been losing men daily, some to gunfire, some to greed as they run off with whatever they think they can sell, but this expedition is costing him, and either Mutt isn’t up to the task, or his heart just isn’t in it, so he figured bringing in dad would either provide a better archeologist, or better motivation. They’re all taken hostage.
It seems Mark Hamill has been bribing the local VC who largely run Hanoi; they’ve been watching Indy since his arrival. Indy bargains with Mark- let his friends go, and he’ll help them finish excavating the Citadel. Mark gives us a fiendish smile, and says that he could always just keep all of them- in case he needed motivation down the line.
A portion of it would likely be almost a prison movie, with our heroes in captivity, working to discover a path through the collapsing citadel or other means for an escape, all while Indy snaps at Mutt for getting them all into this predicament. Mutt eventually explains he’s already found a way down, but needed to be able to get all of them away from their captors. So part of it is a chase through a collapsing, booby-trapped citadel ruin.
Eventually, they all arrive at a chamber just outside the one where Mutt has promised a treasure worth more than anything. Mark and his goons show, but he’s lost enough of them during the chase, that when Mutt suggests they split whatever’s there, instead, partners, like they were always supposed to be, Mark accepts, but reiterates a threat (though it’s our first time hearing it), that if Mutt disappoints him, he’ll shoot him. It’s a combination of Mutt, Indy and Short Round who are able to get the puzzle open, letting them into the room.
We’re going to invent some mythology, because, well, there’s no actual magic in the world, so duh. The history is that the Nguyen Dynasty moved the capitol from Hanoi. It maintained the name “Long” but purportedly this no longer referred to the Imperial dragon (as it was no longer the Imperial seat), but instead to longevity and prosperity. But the rumor was there was actually a second Nguyen ruler; the two brothers reunified Vietnam together, but then couldn’t decide who would rule. They left it to their soldiers, who sided with the historical ruler. However, the other brother refused to yield his claim, and fortified Hanoi as his capitol.
The historical ruler tried to take the citadel by force. Several times the citadel was captured, all inside slaughtered. Assassins a dozen times over swore to delivering fatal blows to the brother, only for him to be alive and defiant the next day. The legend says that while he held one of the last phoenix feathers, no blow, no matter how ruinous, could be fatal. Rumors are one of the other feathers found its way into the hands of Rasputin, that it wasn’t until the Neva River finally tore it from his grip and he drowned. Eventually, the historical ruler recruited a girl who his brother had loved from afar their entire lives; she stole the feather, and all of his brother’s wounds returned, killing him instantly. The girl had not known that stealing the feather would harm him- his brother had convinced her it was a game between them- and it burned in her fingers, catching her dress alight and disfiguring her.
The legend went that she slunk to the catacombs beneath the citadel, where she cared for the last breeding pair of phoenixes in the world and mourned the fallen Nguyen, who she, too, had loved. Supposedly, she and the remainder of the dead Nguyen’s household remained, spawning generations that kept the birds and their progeny alive.
I like the idea that this is the reason Mutt’s been such a mutt- that he was seeking the phoenixes purported to have existed within the citadel. It was so risky he had to work with scum and thieves, because they were the only ones greedy enough to try for this score in the middle of a literal warzone.
The reason is the drink from the Grail is clearly failing his father; immortality might have come from repeatedly drinking from it, but the sip Indy took only made him look pretty good for his age, and Mutt’s not ready to lose Indy (I think we can all relate).
And that’s why it’s such a blow when they finally breach the interior chamber of the citadel. Because all they find is death- but recent death. The stories were true, that a dedicated group had managed to keep these magical, mythical creatures alive for hundreds of years, only for imperialism and war to murder them (personally I’d go with shelling from the Vietnam war killing them, but the French colonial invasion could work, too). It’s a heart-wrenching blow, especially to Mutt.
And that’s when our villain shoots Mutt in the back. “I told you what would happen if you failed,” Mark Hamill says, and grabs the field med kit Sallah brought, rushing for the door and knocking the supports loose, leading to a collapse that will trap the rest of them inside. Indy and Short Round manage to roll through just before the collapse, Short Round losing his hat. Indy tells Sallah to move the rocks. They’ll be back with help.
Mark’s got a martial artist sidekick who he sends to slow them down. Short Round fights him while Indy chases Mark. We’ll cut back and forth between the two fights, but I expect this one to be the impressive one; the other fight is going to be two grampas wrestling (and there’s only so much you can hide that with stunt doubles and quick cuts). If we want to amp it up, the other fighter grabbed a handful of phoenix down from a smashed egg, so he takes a repeatedly licking until Short Round manages to knock him off the citadel, and he drops the down as he falls.
Mark climbs higher, up the parts of the citadel that still climb into the sky. A portion has a very shaky stone bridge to a nearby structure, and Mark runs along it, stopping to cause a partial collapse to prevent Indy from pursuing. Indy swings with the whip in front of Mark, knocking him over, causing him to cling to some of the remaining stones, as he howls, “That’s impossible.”
“I know,” Indy says, because I can’t resist dueling Star Wars references. “Now give me the bag.” Mark dangles it precariously over the edge. “My son dies, and you do,” he says, his hand hovering over the gun in his belt. Mark tosses him the kit. He throws it across the gap to Short Round. I think more of the rock bridge collapses, and Mark starts to fall, to be caught by Indy, who pulls him up. Personally, I’d keep Mark around, treat this kind of like the Fast franchise, and have the more interesting bad guys stay and be frenemies, but if you want to go for maximum villain, this would be the moment he tries to press the advantage to stab Indy, and that makes Indy drop him.
Indy swings back across the gap, and arrives as Short Round is bandaging Mutt. “He’ll live,” he says.
Indy helps Mutt up off the ground. “You’re a lousy archeologist. But I never wanted you to follow in my footsteps. I just want a chance to know my son.” He supports Mutt as he hobbles out of the room, before he stops, and sets his hat on Short Round’s head, and says, “You did good today, kid.” Because seriously, Short Round is a million percent the better inheritor of his legacy. What Mutt needs isn’t a hat, it’s time with his father.
But I do have one, final trick up my sleeve for this franchise:
At the end of the credits, we plant our flag, with, “Short Round will return in Indiana Jones’ Legacy.”
For this series follow-up series we’d pay Harrison Ford to record as much voice over as we could, involving his letters, journals, instructions for Short Round to get/use/destroy/whatever fantastical mystical objects. Indiana Jones couldn’t be everywhere, and perhaps just as importantly, understood he wouldn’t live long enough to see some of the sites that technology would eventually make available. So the framing device is Harrison Ford setting the characters on wild scavenger hunts essentially letting Harrison Ford continue to play Indiana Jones without breaking a leg again. And if either he doesn’t want to do them anymore, or if he can’t, then Short Round can read them, or we can have someone else do it as part of the plot, but it gives us an in to keeping the character involved. I’d also suggest we keep the series roughly 50 years in the past, so as Short Round ages out of the role, we pick up one of his kids, or one of the kids he ends up adventuring with (as one does).