Can Conan locate the Blush Mermaid and beat Kaitou Kid?

Ran, Sonoko, and Conan are watching "Which Sweets Show", a television program where two chefs compete to see who makes better sweets. The defending champion wins again, making him the winner for six weeks in a row. Thanks to Sonoko's father, Ran, Sonoko, and Conan can watch the preview from the show's gallery next week. Sonoko, who needs to invite five people, but she is stuck on the last person to invite.