The mysterious challenger Katsuki defeats Megumi and challenges Danji to a match, but Danji has a condition: to defeat Yu-yu first. And that's how Yu-yu started his special training with Danji for the cardfight one week later...
Our Seven-Day Crusade 
حملة أيّامنا السّبعة
Nuestra cruzada de siete días
Nuestra cruzada de siete días
LA GUERRE DES SEPT JOURS
Nossa cruzada
de sete dias
Наш семидневный крестовый поход