Arusu believes in magic. With all her heart, she believes that magic is possible and that it can be used for good deeds and fun games. But suddenly, she finds herself transported into another world, ruled by a mysterious elite of witches—and these witches don't seem to be in it for the fun. They're hard at work capturing sprites, the native magical beings of the world, and forcing them into slavery. Once Arusu realizes that her new surroundings aren't just a dream, she sets out to change things.

The series aired on NHK Educational TV from April 9, 2004, to March 4, 2005, with a 6-episode OVA spin-off titled Tweeny Witches: The Adventures released on November 22, 2007. In North America, Media Blasters released the series and OVA in 2008 and 2009 respectively, both dubbed and subbed.