For detailed information about this series, see: Kaeru no Tame ni Kane wa Naru at Wikipedia
Kaeru no Tame ni Kane wa Naru (For the Frog the Bell Tolls) is an action role-playing videogame created by Nintendo and released only in Japan on September 4, 1992 for the Game Boy. It was re-released for Nintendo 3DS Virtual Console on September 5, 2012, yet only in Japan.
A Game Boy Color remake titled Kaeru no Tame ni Kane wa Naru DX was planned for a 2002 release, but was ultimately scrapped.
The story is about two princes, the player character, Prince of the Sablé (or Sabure) Kingdom, and Richard, prince of the Custard Kingdom, who compete to save Princess Tiramisu and the Mille-Feuille Kingdom. During the adventure the two princes and many other people are turned into frogs, and only the sound of the Spring Bell would turn them back, hence the name of the game.