S1·E29 Trick

Baku meets Minami, who has become an agent, in a dream. Baku helps Minami with her mission to find a lost cat, but they are attacked by a Nightmare, and he wakes up.

A "Black Case" has occurred in which Minami has grown a cat's tail. When Baku falls asleep again, he challenges the Nightmare to battle in order to save Minami, but...!