Various people find themselves on a mysterious train with an endless number of cars, each one being its own universe, and they must find a way to get home in this animated anthology series.
Compared to the imagination of previous seasons to the point of high-octane nightmares, Book Four is more subdued. This season was not intended to be a finale season and feels more at place if it was in the middle.
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.
It's a shame that this will be a farewell as Book Four is where the creative team behind it seems to have really hit their stride while also being able to take big swings. Not all of them land, but when they do, well, there's nothing quite like it.
The result is the show's most emotional season, and also its most heartwarming. Duet speaks to the ethos at the core of Infinity Train: that we all have a chance to do better and get better.
