Smacking butterflies around: Time travel and choices in Sci-Fi

This blog post will contain spoilers for Doctor Who, Star Trek, and The Animorphs. Specifically, the Doctor Who episode “Turn Left”, the Star Trek episode “Yesterday’s Enterprise”, and Megamorphs 4, “Back to the Before”.

I grew up digging sci-fi stories from a very young age. I have weirdly specific memories of watching Star Trek with my parents in our living room and watching Star Wars with my brother and sister on a CRT TV we jerry-rigged to be hooked up in the back of our Suburban on a family road trip. As I grew older, I consumed more and more, specifically getting into Doctor Who and Star Trek (again) when I was in college. It doesn’t even need to be good sci-fi for me to dive right in, I even like the trope-filled stuff. In fact, sometimes tropey sci-fi is the best, and one of my favorite tropes is stories that look at the idea of a butterfly effect. Show me a story where changing one decision in the past ripples through time, and I am 100% there. This past week, I reexperienced two stories that follow that idea, which reminded me of a third, and found some interesting similarities in all three.

Image from Seerowpedia

The first one I started this past week was the fourth Megamorphs book in the Animorphs series. For those who aren’t familiar, the Animorphs books tell the serialized story of a group of teens who get swept up in a guerrilla war to stop the covert enslavement of the human race by a race of mind-controlling slugs called Yeerks when they cut through a construction site on the way home from the mall and are given the power to transform in to animals by a dying warrior. Each book in the series is told from the perspective of one of the teens, except for the Megamorphs books, which can change narrators on a chapter by chapter basis. Megamorphs 4, “Back to Before”, starts off from the perspective of the leader of the group, who is tempted by an evil, ultra-powerful alien named Crayak to abandon his fight by allowing time to be rewritten so that the team never walked through that construction site. The book then jumps back to the start of the series and goes through a series of catastrophic events that never happened in the prime timline, thanks to the intervention of the Animorphs. The most empathetic member of the team, Cassie, seems to be aware that things aren’t right from the very beginning, and eventually pulls most of the group back together. Ultimately, the Yeerks start an all-out war against humanity, and 4 out of the 6 Animorphs end up killed (two while they are the active narrators!) before Crayak calls an end to the altered timeline, as he has come to the realization that Cassie is sub-temporaly fixed, or some such nonsense, and therefore this new timeline would never work. Everything gets reset back to where the book started, and only Cassie is left with a vague memory of what happened.

turn left
Image from

Over in Doctor Who, near the end of David Tennant’s run, the Doctor, a Time Lord who travels through time and space righting wrongs and battling evil, and Donna, his human companion, stop off at a market on an alien planet in the episode “Turn Left”, where a fortune teller pulls Donna away, and affixes her with a weird, time-energy consuming bug who takes her back to a single decision (specifically a turn at an intersection) which determined whether or not she’d meet the Doctor. Based on turning differently, the Doctor and Donna never meet, and the Doctor dies during what should have been their first adventure. Donna actually sees the Doctor’s body being carted away, and so does Rose, a former companion who does all sorts of weird timey-wimey-alternate-reality stuff. The episode then goes through a series of time jumps, showing us just how wrecked Earth becomes without the Doctor’s oversight. A hospital full of people (including Martha Jones, another companion) is killed by aliens, the Thames is drained in an explosion, and, eventually, London is destroyed by a crashed, space-fairing replica of the Titanic. This leaves England decimated, and the population (including Donna and her family) live as refugees in their own country, until the military starts rounding up any foreigners and sending them to “labor camps”. Throughout all these atrocities, Donna keeps coming across Rose (who refuses to introduce herself), until eventually Rose convinces Donna to come with her, introduces her to time travel, and sends her back in time to prevent her changed decision, warning her that she’ll have to die to do so. Donna ends up throwing herself in traffic to cause a back-up, convincing her prior self to turn towards the right timeline with the Doctor. When Donna comes back to the market in the present (and in the correct timeline), she only has a faint memory of her experience.

Image from

Thinking about those two stories reminded me of one of my favorite Star Trek: The Next Generation episodes, “Yesterday’s Enterprise”. In this episode, the exploratory and diplomatic priorities of the Enterprise are suddenly replaced with a military mindset, including new uniforms, hip-mounted phasers on every crew member (including the return of definitely-already-dead security officer Tasha Yar), and a ruthless attitude. The ship, NCC-1701-D, comes across another Enterprise, NCC-1701-C, coming through a portal in time. With their war with the alien Klingon Empire going poorly, the modern Enterprise convinces the relic from the past to stay and help the fight, especially because when they were displaced from time they were just about to be destroyed by another group, the Romulans. Everyone is on board with this plan except for the ship’s bartender, Guinan, who knows without a doubt that something is wrong. Ultimately, the crew decides that if the Enterprise-C had been destroyed by the Romulans, it could have altered the United Federation of Planets relationship with the Klingons, and the C prepares to go back in time to sacrifice itself in pursuit of peace. Guinan specifically knows that Yar should be dead, so the security officer decides to go back with the C as their tactical officer, to really go out with a bang. Of course, as soon as the C goes back, everything resets to normal, and no one remembers what happened… except for that Guinan asks Data to tell her about Tasha Yar.

I love all of these stories because the idea of such drastic change from such small moments makes me reflect on the decisions I make in my own life. Specifically, it makes me realize that it’s futile to dwell on mistakes because you never know how doing something differently would have caused ripples down the line. There are two commonalities in these three stories I noticed that are really intriguing to me. First, every single story has a character who is aware that things aren’t the way they are supposed to be in the altered timeline, and, second, every single one ends with only one character remembering the alteration. I wonder if there are examples of these stories that don’t fit those trends, either by having all character fully absorbed in the alternate timeline or by having everyone impacted remember the changes after the fact.

If you can think of any stories that break this formula – or even have a favorite in the formula that I missed – let me know in the comments below, but please be sure to include spoiler tags!

2 responses to “Smacking butterflies around: Time travel and choices in Sci-Fi”

  1. […] can find some prior blog posts about Animorphs here, here, here, here, here, here, here, and here… I kinda love these […]


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