“The 100” may be blowing through its fourth season with the promise of a fifth, but the show knows how to honor its history, that’s for sure. Wednesday’s (March 29) episode, “God Complex,” managed to drop a handful of callbacks to earlier seasons into the narrative pretty seamlessly, reminding us what we loved about the show in its early days.

A beloved episode from Season 1 called “Day Trip,” gets the first shoutout. Most remember it for the major Bellarke feels it gave us, but you might also recall the trippy mass hallucination the kids went through back at camp thanks to some pretty potent Jobi nuts.

Jasper’s (Devon Bostick) quest to live life like he’s dying put him on a quest to get more of them for a rager he was throwing back at Arkadia. In theory, it sounds like a bad idea to risk being caught in acid rain just so you can get super duper high, but that’s pretty much where Jasper’s head is at right now.

RELATED: ‘The 100’ needs to pick a survival plan and stick to it

Bellamy accompanies him, which leads us to callback number two: “Whatever the hell we want.”

We honestly hadn’t drawn a parallel between Jasper’s new carefree mentality and Bellamy’s Season 1 slogan, but it’s nice to see it adapted for Season 4. This time, it’s not so much a symbol of freedom as it is a reminder that there is a ticking clock on all this fun Jasper is having. We’re not so sure he’s going to be so laissez faire when he’s dying a slow, radiation-soaked death, but that’s a problem for another day.

“God Complex” also saw the return of a Bellamy we haven’t seen in a good long while. Party Bellamy.

Thanks to the weight of  his own guilt and the responsibilities of being a leader, he’s been saddled with some heavy plots the past few seasons. Subsequently, we haven’t gotten to see Bellamy cut loose very much. Most fans will remember Season 1 Bellamy though, who spent his time partying with delinquents and having threesomes.

It’s been too long since we saw Bellamy smile and enjoy himself, and we hope he continues to find a few of these lighter moments amidst the doom and gloom of the impending apocalypse.

Finally, the biggest callback this week was the theme of “survival requires sacrifice.”

It’s a notion that has never really left “The 100,” but Clarke (Eliza Taylor) and Abby’s (Paige Turco) dilemma about sacrificing innocent people for the greater good felt like a direct callback to the pilot. The decision to risk one life in exchange for saving thousands seems like easy math to make sense of, but it’s never that simple on “The 100.” Abby’s line from the pilot, “I choose to make sure that we deserve to stay alive,” felt particularly relevant to the situation at hand.

It was odd to see Abby and Clarke at the helm of the experimentation argument, considering they’re usually on the side of doing the honorable thing, even if it isn’t the most rational. This time, they were desperate enough to risk their humanity in order to save their people, even if it meant killing Emori (Luisa D’Oliveira) in the process.

RELATED: ‘The 100’: Murphy & Emori are a match made in psychotic heaven

Ultimately, we’re glad Clarke decided to inject herself with Luna’s (Nadia Hilker) bone marrow instead of Emori. Things have gone to an incredibly dark place this season, and it’s a nice reminder that Clarke is, at her core, the hero of the story. Heroes sacrifice themselves to save others; they don’t kill innocents for their own benefit, no matter how many reasons or justifications they can come up with.

The sacrifice ended up being pretty pointless in the end, considering Abby decided to destroy the radiation machine rather than risk Clarke’s life.

We curious what will come of Clarke being a Nightblood now. If Jaha’s (Isaiah Washington) new bunker can indeed save everyone (Grounders and Skaikru alike), then it won’t be necessary to distribute Abby’s treatment to the masses. That means that besides Luna, who refuses to take The Flame and ascend to the position of Commander, Clarke is the only Nightblood left.

Who’s to say if she’ll become Commander or not — or whether the people would even support her if she did — but it at least presents the possibility of more Clexa scenes, even if it’s only a digitized memory of her in Clarke’s head.

“The 100” airs Wednesdays at 9 p.m. ET/PT on The CW.

Posted by:Lindsay MacDonald

Lindsay MacDonald is a Los Angeles based entertainment reporter with an affinity for CW superheroes. She graduated from Pepperdine University with a major in Media Studies and a borderline unhealthy obsession with TV in 2012. She would much rather spend the day binge-watching ‘The Flash’ or sorting ‘Game of Thrones’ characters into Hogwarts houses than venturing outdoors. TV words to live by: “Never ignore coincidence. Unless, of course, you’re busy. In which case, always ignore coincidence.”