Shinsuke and Shakugan are staying with Jinka and Tama, but Shinsuke isn't learning much in the way of fighting skills. Instead, Shinsuke is left behind to do chores when Tama and Jinka are informed of trouble with a local katawara.  
A challenge?
تحدي؟
Eine Kampfaufforderung?
¿Una carta de duelo?
¿Una carta de duelo?
Une lettre de défi ?
Una lettera di sfida?
Uma carta de desafio?
Испытание?