Join In! Rivals

'''Join In! Rivals' (参戦！らいばるたち, Sansen! Rai barutachi) is the tenth episode of the first season of Isekai Quartet'' and tenth episode of the full series overall. It aired on June 11, 2019.

Summary
It's time for Field Day, and Roswaal hints that whoever wins will get to go home. But then they meet their opponents…