After entering the mysterious Train, Professor Sycamore finds himself in a forest where he's taken in by a Demon Lord of the Monster City. Meanwhile, everyone back home realized that the Kalosian professor has vanished and Calem is forced to contact a few people he knew who are connected to the Train.
This arc contains examples of:
- Bait-and-Switch: Rimuru is horrified when he learns that Shion is cooking for Professor Sycamore and Garchomp and races off to stop them. Too late, the food is already eaten...and Professor Sycamore states it's delicious! Unfortunately, Garchomp got food poisoning...
- Break the Scientist: Professor Sycamore, unfortunately, had several moments the moment he wakes up on the Train. Just seeing Gobta and the other Goblins and a talking slime, Rimuru, makes him Faint in Shock twice!
- Big "NO!": One of Calem's friends texts this when Calem reveals that their former theory of "The Infinity Train only picks up kids" is debunked.
- Drama-Preserving Handicap: A Garchomp with Mega Evolution would be perfect to help out against the Rock Golems. If only she didn't get food poisoning...
- Expecting Someone Taller: Sycamore sees a butler in a black suit — Diablo — is the so-called Demon Lord. Nope, it's the blue slime blob he's holding.
- Internal Reveal: Part 3 has Sycamore learn that Alain was also picked up by the Train. The following chapter has him learn about the Infinet service and of the Red Lotus Trio.
- Lethal Chef: Shion, even with her [Chef] ability is a horrible cook. However, Professor Sycamore stated her "soup" was delicious while Garchomp was knocked unconscious.
- Poor Communication Kills: Augustine doesn't learn until a week into his stay at the Train that there's now a working Internet system that he can use to talk to everyone. Justified because One-One hasn't updated the introduction videos to include that factoid yet. Needless to say, the professor is not happy to learn this.
- Shout-Out: The whole car is a huge shout-out to That Time I Got Reincarnated as a Slime.
- The Reveal:
- Calem is friends with former passengers of the Train.
- Alain Sativus actually passed by the Monster City Car and saved it from harm.
- Training from Hell: Both Sycamore and Vaillant engage in this with Hakurou as their master in preparation for the next raid as well for the former not to rely on his Garchomp all of the time for his journey.
- Wham Shot: Part 3 reveals that Alain Sativus passed by the Monster City Car.
