Nurse Angel Ririka SOS (ナースエンジェルりりかＳＯＳ, Nāsu Enjeru Ririka EsuŌEsu) is a Japanese shōjo manga series created by music producer and television writer Yasushi Akimoto and manga creator Koi Ikeno. The manga was serialized in Ribon Magazine from January 1995 to June 1996, and subsequently collected into four bound volumes published by Shueisha. The story follows Ririka Moriya, an elementary school student who receives the power to transform into the legendary guardian, Nurse Angel. As Nurse Angel, she is the only person capable of protecting the Earth from world-destroying invaders.