Happy Death Day 2U (2019) & The Endless (2017): Time-Loop Horror | EP15
- Nov 19, 2020
- 3 min read
Updated: Mar 9
Cosmic Time Loops.
In this episode of Journey Through Sci-Fi, we continue our exploration of the time travel subgenre by looking at two films that push the idea of the time loop in very different directions.
Both Happy Death Day 2U (2019) and The Endless (2017) explore what happens when characters become trapped inside repeating moments in time — but they approach the concept from opposite ends of the sci-fi spectrum.
First we discuss Happy Death Day 2U, the sci-fi horror-comedy sequel that expands the time-loop premise of the original film. The story once again follows college student Tree Gelbman, who finds herself reliving the same day after a physics experiment accidentally creates a time-loop across parallel realities.
Then we explore The Endless, the indie sci-fi horror film about two brothers who return to a mysterious cult they once escaped — only to discover that strange cosmic forces appear to be trapping people inside repeating loops of time.
Together these films demonstrate how the time-loop concept can evolve into very different kinds of science fiction storytelling — from high-concept genre comedy to unsettling cosmic horror.
Because here on Journey Through Sci-Fi, we explore the history of science-fiction cinema one subgenre at a time.
Listen to the full episode below:
What We Discuss In This Episode
In this episode we talk about:
• The evolution of the time-loop trope in modern sci-fi
• How Happy Death Day 2U expands its premise into parallel universes
• Cosmic horror and time loops in The Endless
• The difference between comedic and existential time-travel stories
• Why time loops remain one of science fiction’s most flexible ideas
Happy Death Day 2U (2019) – The Science Behind the Time Loop
Directed by Christopher Landon, Happy Death Day 2U builds on the time-loop premise of the original film by introducing a more explicit science-fiction explanation.
The story once again follows Tree Gelbman, who discovers that a physics experiment conducted by her classmates has accidentally created a temporal anomaly. This experiment traps her in a repeating day within an alternate reality.
As Tree repeatedly relives the same events, she must work with her friends to understand the device that caused the loop and find a way to return to her original timeline.
The film blends time-travel mechanics, parallel universes and comedy-horror, showing how flexible the time-loop concept can be.
The Endless (2017) – Time Loops and Cosmic Horror
While Happy Death Day 2U approaches time loops with humour, The Endless presents a far more unsettling interpretation.
Directed by Justin Benson and Aaron Moorhead, the film follows two brothers who revisit a remote cult they once escaped. As they reconnect with the group, they begin to notice strange phenomena suggesting that the area is controlled by a mysterious cosmic entity manipulating time.
Certain individuals appear to be trapped inside endlessly repeating events, forced to relive the same moment again and again.
The result is a unique blend of science fiction, horror and existential mystery, where time loops become part of a much larger cosmic puzzle.
Time Loops Across the Genre Spectrum
Both Happy Death Day 2U and The Endless show how versatile the time-loop concept has become within science fiction.
In one film, the loop is a puzzle to solve — a scientific anomaly caused by experimental technology.
In the other, it is something far stranger: a cosmic force beyond human understanding.
Together they demonstrate how modern sci-fi continues to reinvent the time-travel genre.
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About Journey Through Sci-Fi
Journey Through Sci-Fi is a podcast exploring the strange, visionary and world-changing history of science-fiction cinema.
Each series focuses on a different sci-fi subgenre, examining the films and ideas that shaped the genre - from classic cinema to modern science-fiction storytelling
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