Working as an underwater sanitation engineer, Jem has developed a hostility toward land dwellers. She encounters garbage from land dwellers all day long, such as six pack carrier rings, plastic bottles, bags of cash, treasure chests, and more. No matter how much she clears, the garbage never stops coming, driving her to insanity.
Each mastery level adds another card to the cardpool for defeating Jem. Each of the bronze, silver, and gold mastery levels unlocks a new card, while it takes all three diamond and onyx levels to unlock a single card.