Unintended Exchange - Isekai Quartet Oneshot

Subaru presses a red button - the same red button that had sent everyone to this school world - hoping it would send him back to Lugunica or Earth. However, it creates an unintended exchange instead with a fellow classmate.

In other words, Kazuma wants to have the time of his life, and Subaru wants things fixed ASAP.

Cross-posted to AO3 and Quotev.