I'm not sure what you mean by "explain." It's basically a 4th menu on the 4 day cruise. For the first 3 nights you have rotation dining where the menu and theme are tied to the restaurant that you are in. On the 4th night you are back in the restaurant that you were in on the first night and everyone in every restaurant has the same menu, the master chef series. I believe the master chef menu basically is a conglomeration of specialties of various disney restaurants and menus (including past cruise menus that no longer are being served). Does that help?