In the ending of Golden Sun, Isaac and his companions fought a fierce battle at the top of the Venus lighthouse. Despite claiming victory, they weren't able to keep the lighthouse from being ignited, and a tremendous explosion followed. The Lost Age picks up where Golden Sun left off, with characters from the original game regrouping to prevent the destruction of their world. Meet and join up with new characters along the journey and experience a story far more expansive than Golden Sun.
This game is also known as Ougon no Taiyou: Ushinawareshi Toki in Japan.