Who Smeared the Zebu?

Overview

The Zebu is a candidate for zoo director. One morning, during a press conference, he gets a creampie in the face. The picture is front page news in the zoo. Who threw the pie at him? Sherlock's investigation leads him to the other candidates in the election. In the meantime, Hermione thinks that Sherlock should stay on as current zoo director. But how can she convince him not to retire?