Season 1
It is a normal day; everyone from deranged military girl Tanya Degurechaff and 16-year-old isekai protagonist Satou Kazuma to expansionist overlord Ainz Ooal Gown and demon sisters Rem and Ram go on with their daily lives. Suddenly, a conspicuous red button begging to be pressed appears before them. Overcome by curiosity, the otherworldly characters push the button, sending them to an unfamiliar world.
With no way of escaping, the characters must lead a normal school life and make acquaintances with the others. One thing is certain: the classroom full of fan-favorite eccentric personalities never gets boring!
01. Come Together! Quartet
Mysterious buttons appear in the worlds of Tanya the Evil, KonoSuba, Overlord, and Re:Zero. When the characters push them, they're taken to a place they'd never imagined...
02. Tension! Introductions
Now that everybody's settled in, it's time for the first day of school, which means everybody has to introduce themselves.
03. Deadlock! Classmates
The students begin to wonder about why they are here, and what this school really is. Tanya, in particular, has a theory about Ains...
04. Encounter! Classmates
The students realize that they're all from other worlds, and begin to share their backgrounds. But some are luckier than others...
05. Explosion! Talent Show
It's time for the talent show, but none of the students are talented at all. The KonoSuba crowd in particular...
06. Decision! Class Rep
It's time to pick the class rep! But Aqua doesn't want Ains to do it, and Albedo doesn't want Aqua anywhere near the job.
07. Carry Out! Class Rep
Emilia's the class rep now, but it's really hard. But she wants to do her best!
08. Prepare! Field Trip
It's time for a field trip to the beach, and the gang's getting ready. But who wants to see Kazuma in a swimsuit?
09. Enjoy! Field Trip
The field trip is here, and it's great! Everybody's at the beach and having a great time. But Tanya hears something that makes her upset...
10. Join In! Rivals
It's time for Field Day, and Roswaal hints that whoever wins will get to go home. But then they meet their opponents...
11. Work Together! Field Day
Field Day is here, and it's lots of fun for everyone. There's tug of war, scavenger hunts... and giant robots?!
12. Band Together! Quartet
The mobile fortress "Destroyer" has joined the last game! It's up to the quartet to grab its headband and win the game.