Updated on Dec. 7 at 8:38am ET: We've got the Avengers 4 trailer below, which reveals the full title of the movie and its new, earlier release!
Ever since the credits rolled on Avengers: Infinity War, we've put one question above all others: "When do we get to see what happens next?"
Details of Marvel's next big Avengers movie are scarce right now, but we've been able to piece together some key details thanks to the myriad of teases and leaks on the web.
Before we continue, know that this story will feature spoilers for the Marvel Cinematic Universe movies, including Avengers: Infinity War.
Here's what we know, true believers:
When is Avengers 4 coming out?
Back in October of 2014, before we knew how shockingly Avengers: Infinity War would end, Marvel announced that "Avengers: Infinity War Part II" would release on May 3, 2019.
Much like the ranks of still-alive Avengers, that's changed. In the first trailer, Marvel announced that the next Avengers film is actually coming out in April, instead.
How do I watch the Avengers 4 trailer?
On Friday, Dec. 7, Marvel Studios published the Avengers 4 trailer online, and here it is:
Early speculation suggested the title would be Infinity Gauntlet, Marvel exec Kevin Feige threw cold water on that name.
The Endgame title definitely confirms another hint. An early clue as to the title came from the Russo brothers, who directed Infinity War. In a long-since deleted tweet, that Inverse reported on, a Twitter user named 
That pushed fans to think the new film's title will be very doom and gloom, such as Avengers: Annihilation.
Who's in the Avengers 4 cast?
Before we get to the cut and dry list of the Avengers 4 cast, as credited on IMDb, let's talk basics. The core Avengers (2012) film cast — Robert Downey, Jr. (Tony Stark/Iron Man), Mark Ruffalo (Bruce Banner/Hulk), Jeremy Renner (Clint Barton/Hawkeye), Scarlett Johansson (Natasha Romanoff/Black Widow), Chris Evans (Steve Rogers/Captain America) and Chris Hemsworth (Thor) — are all coming back.
In the trailer, we saw all of those actors, plus Karen Gillan as Nebula and Paul Rudd as Ant-Man.
We'll also see other Infinity War survivors — Nebula, Rocket and War Machine — and how they're dealing with a world where half of their friends don't exist anymore.
After Infinity War spent a lot of time with the characters introduced since the first Avengers film, the fourth Avengers film will likely find the core six righting the wrongs of Thanos' world-halving move. In terms of new characters, Avengers 4 will be the first in the series with Captain Marvel (Brie Larson), who debuts in her own film (coming March 2019), but the film will be the first MCU film for Katherine Langford (13 Reasons Why), who's playing a to-be-announced role, which is possibly an older version of Ant-Man/Scott Lang's daughter.
MORE: Upcoming Marvel Movies: A Timeline of Release Dates
And now, it's time to bring out your dead. While many, many characters died at the end of Infinity War, nobody is off the table, especially with the Time, Soul and Reality Gems in play to send Avengers back in time, bring the dead back to life and warp the perceptions of others.
So, yes, there's no way to be sure you've seen the last of Tom Hiddleston as Loki (he's coming back for a Disney Play series, by the way), Idris Elba as Heimdall, Zoe Saldana as Gamora, or Paul Bettany's Vision. And those are just the characters who died before The Great Snappening.
So, yes, don't expect you've seen the last of Chadwick Boseman as T’Challa or Black Panther, especially as there are more Black Panther movies coming. Someone else — Okoye (Danai Gurira) or Shuri (Letitia Wright) are top options — may take the mantle in his absence, though.
Also set for a sequel are Tom Holland's Peter Parker, who's due to appear in Spider-Man: Far From Home next year.
Don't be surprised to see some, if not all of the rest of the snapped-off folks — who include Doctor Strange (Benedict Cumberbatch), Bucky Barnes/Winter Soldier (Sebastian Stan), Falcon/Sam Wilson (Anthony Mackie) Scarlet Witch/Wanda Maximoff (Elizabeth Olsen), Star-Lord (Chris Pratt), Nick Fury (Samuel L. Jackson) and Maria Hill (Cobie Smulders) — in Avengers 4.
In an interview with E! News, Zoe Saldana stirred speculation that Gamora will return, and Tessa Thompson will likely be reprising the role of Valkyrie, according to co-director Joe Russo.
A longer list, sourced from IMDb on Oct. 29, includes:
Robert Downey Jr. as Tony Stark / Iron Man
Chris Hemsworth as Thor
Scarlett Johansson as Natasha Romanoff / Black Widow
Chris Evans as Steve Rogers / Captain America
Mark Ruffalo as Bruce Banner / Hulk
Elizabeth Olsen as Wanda Maximoff / Scarlet Witch
Dave Bautista as Drax
Pom Klementieff as Mantis
Jeremy Renner as Clint Barton / Hawkeye
Chadwick Boseman as T'Challa / Black Panther
Gwyneth Paltrow as Pepper Potts
Letitia Wright as Shuri
Ty Simpkins as Harley Keener
Don Cheadle as James Rhodes / War Machine
Paul Rudd as Scott Lang aka Ant-Man
Tilda Swinton as The Ancient One
Josh Brolin as Thanos
Sebastian Stan as Bucky Barnes / Winter Soldier
Bradley Cooper as Rocket Raccoon
Evangeline Lilly as Hope van Dyne / The Wasp
Karen Gillan as Nebula
Brie Larson as Carol Danvers / Captain Marvel
Michelle Pfeiffer as Janet Van Dyne
Jon Favreau as Happy Hogan
Frank Grillo as Brock Rumlow / Crossbones
Do we know anything about the actual plot of Avengers 4?
Aside from the obvious, that it will set the remaining, living Avengers on a path to restore order and stop Thanos? No, not really. The big clue set forth in Infinity War was that Doctor Strange had found only one future, in the 14 million possible futures, where the Avengers defeat Thanos. He said that line to Tony Stark, who will likely go about reverse engineering that solution.
That solution likely involves Captain Marvel, who Nick Fury summoned as a sort of grand Hail Mary pass at the end of Infinity War. Other key ways to beat Thanos likely include resolving the bad blood between Tony Stark and Steve Rogers, and getting the Hulk to come out of hiding.
Other speculation — tied to hair styles of stars on the set of Avengers 4 — suggests that the Time Gem will be used to send some of our heroes back to the battle of New York in the first Avengers movie.
Are there any Avengers 4 set photos?
Since principal production has ended on Avengers 4, there's been enough time for set photos to leak. Men's Journal has compiled a bunch that show off new costumes, and GamesRadar's got a shot of Gwynneth Paltrow as Pepper Potts donning what looks like her Rescue armor from the comics.
More clues may be found in an image shared by The Russo Brothers on Twitter, with a caption reading "Look hard…" but they're not obvious.