The existence of Marvel’s latest short film has been stirring speculation for weeks, though no one knew for sure exactly what it was, who stars in it, or what the title means.

What is Item 47? Now, finally, some answers.

The film is the latest in the company’s series of shorts dubbed “One-Shots,” a comic book term for stories that wrap up in one issue. Lizzy Caplan (Party Down, pictured) and Jesse Bradford (Flags of Our Fathers) star as a down-on-their-luck couple who find one of the discarded alien guns from the finale to The Avengers — and proceed to make some incredibly bad decisions.

Marvel’s One-Shots have been used as bonus features on home-video releases for Thor and Captain America, and this one will be available Sept. 25 on The Avengers Blu-ray, with a special screening planned for San Diego next week during Comic-Con.

This is the longest, most elaborate of the Marvel shorts so far, and could be a first step toward using short-subject films to dive deeper into the Marvel universe and introduce beloved but less-familiar superheroes to the mainstream.

Item 47 refers to the gun itself, which S.H.I.E.L.D. would like very much to retrieve from the hapless young troublemakers. “The world is topsy-turvy now. There’s been an alien invasion, and things are crazy,” explains Marvel Studios co-president Louis D’Esposito, who directed the film himself. “So when this gun ­literally fell into their lap, this is a sign: We’re going to rob a few banks, we’re going to buy a boat, we’re going to the Caribbean, and all our problems will be solved.”

Two S.H.I.E.L.D. agents (Maximiliano Hernández, returning from Thor and The Avengers, and Lost’s Man in Black Titus Welliver, making his Marvel debut) are given the job of cleaning up the mess and stopping this modern Bonnie and Clyde (not coincidentally named Benny and Claire.)

The goal was to show some non-superpowered people reacting to the aftermath of The Avengers. “Anything that expands the world and shows you the more human elements of it, that just makes the world more colorful and fun for the average viewer,” says Eric Pearson, who wrote the screenplay for Item 47, as well as the previous two One-Shots: A Funny Thing Happened on the Way to Thor’s Hammer and The Consultant.

Each starred Clark Gregg as S.H.I.E.L.D. Agent Coulson, but those films were much shorter — no more than 4 minutes, compared to Item 47‘s 12 minute run-time — and they were single scenes with few visual effects or action. Item 47, in contrast, goes on a much bigger ride.

Marvel is exploring whether short films like this could now go even further. The goal is to have a short accompany the home-video for each feature film, and they’re currently devising scripts for companion pieces to Iron Man 3, Thor 2, and Captain America 2.

The question is whether the One-Shots can expand to not just tell not just inconsequential side-stories, but also experiment with longtime heroes who may not yet be ready to carry their own features. A short could be a good test for a Black Panther or Iron Fist or Wasp, for example — characters who are beloved by die-hard fans but less known in the broader culture.

D’Esposito says the company “wrestles” with that idea. “There’s always a potential to introduce a character. We have 8,000 of them, and they can’t all be at the same level. So maybe there are some that are not so popular, and we introduce them [with a short] – and they take off. I could see that happening.”

The risk is establishing the potential movie too much, and then trying to retroactively recruit a feature filmmaker with those creative elements already in place. “Let’s say we wanted to introduce Ant-Man [in a short], and that would mean we have to cast him prior to having a filmmaker. That’s difficult and something we wouldn’t want to do,” D’Esposito says.

But in that case, Marvel’s Ant-Man project has had a filmmaker on board for a long time – co-writer and director Edgar Wright (Hot Fuzz, Scott Pilgrim vs. The World). Sources say he recently did shoot test footage for an Ant-Man film.

That’s not quite the same thing as a stand-alone short, but previewing those scenes publicly – say, at Comic-Con next week, or before any of the Marvel features heading to theaters in the next two years – could still be a way to pump up enthusiasm among fans.

Last year at Comic-Con, producer Joe Roth had 6,000 people cheering for a test reel of Snow White and the Huntsman, which featured samples of trippy visual effects and set pieces director Rupert Sanders intended to create – although it featured none of the actual stars. Still, it led to heightened anticipation for the final product, well before a single frame of the movie was shot.

A Marvel superhero short that stands on its own two legs (or more) would undoubtedly have an even greater impact.

Even if Marvel chooses not to show any Ant-Man teases (no one from the studio will confirm what’s in their showcase), they will be at a theater in San Diego next week to show off Item 47 in its entirety.

A real-life scavenger hunt starts with The Avengers Second Screen app, which will become available as a free download at the iTunes store this Friday. Those who can’t go to San Diego can still use the app to gain access to a clip, but for Comic-Con attendees, it will offer the first clue to finding the trail through the city that ends with a screening on the evening of July 12.

Be sure to grab some shawarma to go, in case you get hungry. Item 47 may be short, but the hunt may take a while.