Not sure about the Mariner because they didn't have one when we cruised but they did have one on the Radiance. It was a flat fee, $45 and this included the meal, dessert and all the wine you could drink. The story started in the Colony Lounge and we were given clues and could ask the characters questions between courses. A fun, entertaining and different dinner.
Teresa and Larry
#36-Carnival Splendor 9/16/12
7 night Mexican Riviera
#37-Allure of the Seas 11/11/12
7 night Eastern Caribbean