The fourth and final season of 'The Umbrella Academy' has 1 end-credits scene. Here's what happens.

• Netflix's "The Umbrella Academy" concluded with a six-episode final season released on Thursday.
• In season four, the Hargreeves siblings again team up to stop the world from ending.
• They succeed in their mission, resulting in a singular, peaceful timeline.

Warning: Major spoilers ahead for season four of "The Umbrella Academy.'"

After four seasons, the wacky and dysfunctional family at the center of "The Umbrella Academy" is saying goodbye.

Netflix's TV series adaptation of the Gerard Way and Gabriel Bá comic book series "The Umbrella Academy" concluded on Thursday with six episodes.

The final season is packed with action, eye-opening revelations, and one last sacrifice to definitively save the world. The finale also includes a quick end-credits scene that ties up the series and honors the Hargreeves. Here's what you need to know.

The Hargreeves siblings sacrifice themselves to definitively save the world one last time

Season four picks up after Luther (Tom Hopper), Diego (David Castañeda), Allison (Emmy Raver-Lampman), Klaus (Robert Sheehan), Number Five (Aidan Gallagher), Ben (Justin H. Min), Viktor (Elliot Page), and Lila (Ritu Arya) landed in a reset timeline without their powers at the end of season three.

The show immediately jumps ahead six years, with the characters living separate lives away from each other. They're brought together to rescue a woman named Jennifer (Victoria Sawal), who becomes a key part of the final season.

It's revealed that she's the same Jennifer from the mysterious "Jennifer incident" that resulted in Ben's death in the original Umbrella Academy timeline.

In the original timeline, the Hargreeves children were sent on a mission to locate and destroy a deadly weapon held inside a container. When they found the container, Ben disobeyed orders and opened the container, finding a young Jennifer inside and pulling her out. Because Ben didn't follow the instructions, his adoptive father, Sir Reginald Hargreeves (Colm Feore), shot him and Jennifer immediately.

The reason Reginald didn't want the Hargreeves to interact with Jennifer is that she contains a particle called durango that was synthesized by Abigail (Liisa Repo-Martell), Reginald's wife. When durango interacts with marigold, the particle that gives the Hargreeves their powers, the two elements cause an unstoppable physical reaction that can lead to mass extinction — known as the Cleanse.

So, when the Sparrow Academy version of Ben secretly spikes his siblings' shot glasses with marigold, giving them powers again, chaos ensues during the Jennifer rescue mission.

After Ben meets and forms an instant connection with Jennifer, the Cleanse begins to take shape. By the season finale, Ben and Jennifer's bodies break out into glowing red rashes and they morph into one ginormous, destructive creature.

The final season also explains why the Hargreeves are stuck in an infinite loop of time, repeatedly causing and preventing apocalypses in every timeline they encounter.

Through a conversation with an alternate version of himself, Five realizes that his and his siblings' existence is the reason for the fractured, infinite timelines.

The marigold that infected the Hargreeves siblings' birth mothers had an unexpected side effect: it shattered the original timeline and split it into an infinite number of alternate timelines.

To stop the endless loop, the Hargreeves are forced to let the marigold in their bodies merge with the durango inside the Cleanse, so they cancel each other out. But before that, they send Allison's daughter Claire (Millie Davis), Diego and Lila's three kids, and Lila's family to the underground subway station that serves as a waypoint between alternate timelines.

The Hargreeves successfully save the world and eliminate the other timelines, but as a result, they're erased from history and cease to exist.

As the family is engulfed by the Cleanse, a montage of moments from the series plays. Then, the episode cuts to the singular timeline inhabited by the family members they saved and characters from past seasons of "The Umbrella Academy," including The Handler (Kate Walsh), Hazel (Cameron Britton), and Agnes (Sheila McCarthy).

All of the characters are seen playing and picnicking happily in a park. "On the 12th hour of the eighth day of August 2024, absolutely nothing out of the ordinary occurred. You might say it was just a normal day," Reginald concludes in a voiceover.

The end-credits scene pays homage to the heroes

The series finale is bittersweet, capped off with an end-credits scene that honors the Hargreeves' sacrifice.

Even though Luther, Diego, Allison, Klaus, Five, Ben, Viktor, and Lila no longer exist, their memory is kept alive by eight marigold flowers that bloom rapidly in a patch of soil in the park.

"The Umbrella Academy" might be over, but the cast and showrunner Steve Blackman have expressed interest in spinoffs.

"There are ideas, there's things I've talked about, and if Netflix decides down the road, I'd love to do it," Blackman told The Hollywood Reporter. "But ultimately Netflix will make that decision. I hope this isn't the end of 'Umbrella Academy.' I hope there's another iteration somewhere down the road."