Magical Girl Lyrical Nanoha

Riot Force 6's Day Off (First Part) (3x10)

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Subaru, Teana, Caro, and Erio are on their vacation. Suddenly, Erio sensed a magical presence, and follows it. To Erio and Caro's surprise, they see a girl coming out of the sewers. What was attached to that girl's foot was a relic case!