The Moon Kingdom is an imaginary land from the anime, Sailor Moon. It is the kingdom of Queen Serenity, mother of Princess Serenity (Usagi Tsukino, Sailor Moon, past self). The Moon Kingdom was under attack, and Queen Serenity didn't know what to do. She used the Silver Crystal on her daughter, Princess Serenity, and the other princesses (Mercury, Mars, Jupiter, Venus. Ami Mizuno, Rei Hino, Makoto Kino, Minako Aino).