This is Leezera, the capital of Eroolia. Lilia is just an ordinary girl who works in a bakery. She spends every day happily with her childhood friend, Ronan. One day Lilia finds her body has shrunk. Moreover, she has grown cat ears and a tail?! She doesn't know that she's actually a luccretia, a half-human and half-cat creature. She panics, jumps out through her room's window, and runs towards the town. And the first person she bumps into is the city guard, Ronan. The mask of "Big Sis" and "Luccretia Girl" she wears. The mask of "Lil Bro" and "City Guard" he wears. Which one of them will be taken off first?