Picture a 22-year-old inventor face down in Lake Michigan for the fourth time that week. His shoes are pointing backward, his phone is still filming, and his two teammates are watching from the dock with their arms crossed.
That’s the opening energy of Run On Water, a sports comedy screenplay that Reddit user u/cuong_truong built with ChatGPT and shared for free in r/ChatGPTPromptGenius. The hero, Mike Morgan, builds a pair of water-running shoes called the HydroStride X1. He enters a one-mile race across Lake Michigan for a $20,000 prize. Along the way he learns that looking successful and being successful are two different things.
The story is charming. The process behind it is what caught my eye.
Why This One Matters 🧭
Plenty of people ask ChatGPT for a short story and get a wobbly page and a half. A full screenplay is a different animal. It needs a cast, a premise that holds up, an arc that pays off, and a few subplots that don’t wander off and get lost.
This project shows how far a single person can get when they stop treating the AI like a vending machine and start treating it like a writing room.
Look at what’s on the page:
- A clear arc. Mike starts out chasing fame and ends up learning to share credit.
- Setups that pay off. Lauren teaches him short strides and steady cadence. That’s exactly what wins him the race.
- A cast with contrast. Jake is disciplined where Mike is flashy. Joe and Philly’s secret prize-splitting deal falls apart under pressure.
- Stakes under the jokes. There’s a lease on the workshop, a fellowship application, and one genuinely scary electrical malfunction mid-race.
The author also said they used “a lot of prompts” and ran an editorial pass to check for errors. They didn’t paste the exact prompts, so I won’t pretend to know them. The shape of the result still tells you a lot about the method.
How To Build a Screenplay With ChatGPT, Step by Step 🎬
Here’s a workflow that fits what the finished project suggests. Treat it as a starting recipe, not the author’s secret sauce.
- Start with a one-line hook. Something like: “An overconfident young inventor enters a race where contestants run across Lake Michigan in engineered shoes.” If the hook doesn’t make you grin, no amount of formatting will save it.
- Build the cast before the plot. Ask for each main character’s flaw, goal, and what they secretly need. Mike wants fame and needs teammates. That one pairing drives the whole story.
- Write a synopsis before any scenes. Get the beginning, the midpoint mistake, the low point, and the finish on one page. Fix the big problems here, where they’re cheap to fix.
- Break it into sequences. Work through the story in chunks, such as the workshop disasters, the sponsor temptation, and the race. Paste in your cast notes and the synopsis each time so the details stay consistent.
- Draft scene by scene. Ask for one scene at a time with a clear goal, a conflict, and an exit beat.
- Run an editorial pass. Ask ChatGPT to hunt for continuity errors, dropped subplots, and names that quietly changed. The author did something similar and it’s a smart habit.
- Read it out loud. Comedy lives or dies on rhythm, and your ear catches what a model won’t.
Tips & Tricks 🛠️
- Keep a story bible. Keep a short running doc with names, ages, hometowns, and gadget specs. Paste it into every new chat. Otherwise the HydroStride X1 may quietly become the X2.
- Plant, then pay off. Ask ChatGPT to list every setup in your draft and confirm each one gets a payoff. Lauren’s cadence lessons are a good example.
- Give your jokes a job. The best gags here also push the plot, like the backward propulsion and the oversized prize check that won’t fit on the shelf.
- Push back on the first draft. AI tends to resolve conflict too politely. Ask for a harder choice, a worse mistake, or a rival who actually earns the spotlight.
- Fix the ending by hand. The finale lands because Mike gives up the shortcut and shares the credit. That emotional beat is the piece you most want your own fingerprints on.
Your Turn 🚀
You don’t need a Hollywood contract to try this. Pick a silly premise, give it a hero with one big flaw, and spend an evening building the cast and a one-page synopsis. That alone will teach you more about prompting than a dozen one-off requests.
If you want to see what a finished result looks like, the author shared the full screenplay for free on Google Drive. Read a few pages, then tell me which scene you’d rewrite first. Pirates don’t hand out treasure maps every day, so grab this one! ⚓
I used ChatGPT to write this sports comedy screenplay Run On Water
by u/cuong_truong in ChatGPTPromptGenius