Translated, though there's a measure of ambiguity. The cat says 契約者, which means "a person who takes part in a contract"; I'm assuming it's referring to what the girl is doing, so I paraphrased it as seen above. If, instead, the cat already had a contract with the girl, and 契約者 is a term of address, the tl will have to be revised. If someone has seen this anime, let me know.
契約者 (Contractors) enter into a contract with Mysterious Stuff and get one superpower in exchange for having to do some random act (like smoke or fold all the page corners in a book). She isn't one, but she is a professional cosplayer.
It's really good, the writing is miles more clever than anything I've seen come out of Japan in a while. It's sort of boring that all the Contractors have jobs as assassins and have no apparent morals though.
This image (or so I've heard, as it is a parody/fanart of the show) is a reference to "Death Note" (Kiko's "I'm writing your name in the notebook!" line AND her eye colour give hints). Mao thinks Kiko's a contractor, but, as memento mori pointed out, she's one of those anime fans who takes everything that is shown on TV is true.