Part 1: You

[Y/N] is a fable no one has ever heard of. She can turn into animals whenever she wants, which is one of the reasons she stayed mostly unnoticeable. She knows almost everything about everyone, thanks to her abilities. She spies on the people of Fabletown in her animal forms (cats, mice, ferrets...), and now it is her job.

Nobody knows her. There is no written information about her.
But things have changed when Y/N met the sheriff. There is a new criminal on the loose which needs to be caught. Y/N is willing to help the sheriff with the investigation, and Bigby is willing to solve the case with Y/N.