Quote Originally Posted by Tanarii View Post
I haven't seen the movie so I read the Wikipedia plot summary, and it just screams railroad. Otoh Wikipedia plot summaries are usually pretty terrible representations of the actual movies. So what is it about this movie that makes this fantastic to convert to a TTRPG with solid player agency, instead of them just going along for the ride?
My very rough Cliff’s notes cersion of how I’d set it up.

Backstory - can be exposition or result of investigation depending in how long you want to run the adventure for.
15 years ago 5 special forces soldiers stole a a small fortune that was supposed to go to the resistance. The soldiers got ambushed by the enemy after hiding the fortune. 1 was killed, 3 were captured and 1 escaped. The one who escaped came back and took the fortune for himself.
The guy with the money assumes a fake identity and lives a life of quiet luxury, marries a trophy wife while generally keeping hidden.

Inciting Incident
The wife goes away on a personal trip for a few day. She comes back to find their rented house stripped bare. The police arrive and tell ger her husband has been found dead. They tell her he sold the contents of their house in the last few days, but when his body was found they only found a bag with
(1) a ticket to a foreign country (2) his dairy of appointments (3) a selection of false identities and (4) a small selection if random personal items. No money has been found. The police have no leads or clues.

The wife is contacted by an officer of the states secret service. He tells the wife of the true identity of her husband. He tells her that unless she returns the money her husband stole the government can’t help her. He also tells her the 3 remaining members of the team will think she is a part of her husband’s conspiracy.

Recruiting the players
The widow approaches the players. She says she has no clue about her husband’s identity and wants the players to protect her/recover the fortune. Depending on the PCs this may be done on promise of a reward, or with her last cash, or even out of the goodness of their hearts.

Main NPCs
Widow Can either be a complete innocent in over her head, or a femme fatale in in her husband’s plans. She will keep her husband’s personal effects in a safe place.

Evil Guys 1,2 and 3. The former husbands team mates. All are highly competent and highly dangerous. They have banded together on the basis that they don’t trust one another and want to ensure that they each get a 1/3 cut of the fortune.
Each assumes that one of the other 2 killed the husband.
They all ended up in the city after the husband’s identity was made known to them. Possibly his picture was in a newspaper article, possibly they received a tipoff from their informant network, maybe the husband’s anti-scrying protection got compromised - whatever you think of as the DM is appropriate for your setting.
They will try a variety of methods of getting information from the wife - burglary, tailing here, intimidation, seduction. They don't want to kill the wife as she is their remaining lead to the money, but they are ruthless.

Police Detective Inspector plod thinks unsolved murders are messy and wants to tie up and resolve the murder case. He will be reduced to following/investigating the wife due to other leads drying up.

BBEG Is the fake state secret service agent who warned the wife. He is actually the 5th member of the team who got left for dead but didn’t die. He organized of EG1,2 and 3 to find out about the husband. He wants the money and revenge on the team mates who left him for dead.

Optional NPC - Cary Grant Actual state secret service agent. Infiltrates the EG 1,2and 3 group posing as brother of BBEG who wants in on the cut. Wants to recover the money for the government.

Plot
Following the clues from the diary will lead the players on a wild goose chase.

As the players investigate the clues from the widow EG 1,2 and 3 will approach the widow to try and get information from her.
When the party find and confront EG 1, 2 and 3 they will offer to work together to recover the money. Close proximity and police surveillance should discourage the players from killing of The EGs.

The fortune is actually hidden in the non descript personal items in the husband’s personal effects. In the movie it was rare stamps affixed to a letter addressed to the wife, but whatever fits your setting is fine.

The BBEG will attempt to keep the widow distrustful of the PCs and EGs by feeding her information. The BBEG will try to pick off the EGs one by one if an opportunity presents itself to get one in their own.

Climax
The final hint in the diary will lead the group to a location which reveals the nature of how the treasure was hidden (a stamp market in the movie). This reveal will cause BBEG to kill off EG3, and then have a confrontation with the party seeking the treasure.
Optional - Mexican standoff with the BBEG, Widow (femme fatale version) and Cary Grant.