Beloved by many for its ability to explore difficult themes in a compelling, unique way, Infinity Train has had something of a wild ride since premiering on Cartoon Network in 2016. The future of the series -- which was created by former Regular Show writer and artist Owen Dennis -- has almost constantly been up in the air, with vocal fans campaigning to get more Infinity Train using hashtags such as #RenewInfinityTrain and #SaveInfinityTrain. And while Book Four - Duet is currently slated as the show's end, the upcoming season makes a great case for Infinity Train's future.
This time around, Infinity Train: Book Four's central passengers are lifelong best friends Ryan Akagi (Sekai Murashige) and Min-Gi Park (Johnny Young), who, unlike previous protagonists, have not yet been featured in the series. Prior to boarding the train, Ryan and Min-Gi have started to drift apart due to their conflicting goals for after high school. While the free-spirited Ryan wants to pursue a future in music, the subdued Min-Gi has found himself on track for a more normal life. This conflict eventually comes to a head, resulting in them ending up on the titular train at the same time. Ryan and Min-Gi are, with help from a sentient service bell named Kez (Minty Lewis), then forced to solve the train's various puzzles and work on themselves in hopes of getting back to their lives.
At the center of each season of Infinity Train has been a deeply personal conflict or problem through which the central passenger must work. However, with the very train at its own major point of transition, Book Four is all about figuring out how to navigate major changes and the impact those have on others. While Ryan and Min-Gi are separate people with their own personalities and goals, they're still struggling to find their authentic selves. Their long history together also adds a lot of depth to the story and results in the old patterns and dynamics that they've developed impeding them aboard the train. The challenge for Ryan and Min-Gi then becomes how to grow as individuals and friends.
Every season of Infinity Train has brought something new to the series, but Book Four is quite unique, due in large part to the nature of Min-Gi and Ryan's problems. Book Four is, perhaps, most similar to Book Two - Cracked Reflection, which saw MT (Ashley Johnson) and Jesse Cosay (Robbie Daymond) navigate interpersonal relationships. However, the depth and length of Ryan and Min-Gi's friendships results in a significantly more complex -- and at times heartbreaking -- story.
Overall, there's a two-steps forward, one-step back quality to Book Four, as Ryan and Min-Gi backslide into their old habits constantly. The show, though, ends up handling this quite well, and there's always just enough movement forward to keep the Infinity Train from feeling hopeless. Instead, it's more that Ryan and Min-Gi are always on the verge of a breakthrough, but their baggage keeps them from actualizing their revelations.
Book Four's execution is, as one might expect based on previous seasons of Infinity Train, still pretty top notch. Murashige and Young do a great job of communicating just how frustrated their characters are without ever making them too unlikeable. There are also a number of lighter moments -- often as a result of Lewis' Kez -- that keeps Infinity Train from getting unbearably heavy. Plus, the new train cars introduced in Book Four are among the most creative and interesting in Infinity Train's history, though there's still nothing that rivals Book One - The Perennial Child's corgi car.
Currently, Infinity Train: Book Four is slated as the final entry in the anthology series, though Dennis has said he would like to do eight seasons if given the opportunity. While Duet captures everything that has drawn people to Infinity Train, Book Four isn't particularly satisfying as an end to the series. There are still a lot of loose ends and interesting, unanswered questions. This is in no way the fault of the production itself, and the choice not to shoehorn an unfitting ending onto Infinity Train is a good one. The best solution to the problem is then pretty simple: Renew Infinity Train.
Created by Owen Dennis, Infinity Train stars Ashley Johnson, Jeremy Crutchley, Owen Dennis, Ernie Hudson, Kate Mulgrew, Lena Headey, Robbie Daymond, Bradley Whitford, Ben Mendelsohn, Kirby Howell-Baptiste, Kyle McCarley, Isabella Abiera, Diane Delano, Johnny Young, Sekai Murashige and Minty Lewis. Book Four arrives on HBO Max April 15.