Mahou Shoujo Kazumi★Magica: The Innocent Malice

A teenager named Kazumi is kidnapped and placed inside a trunk by an unidentified attacker. After escaping, she finds herself without her clothes and unable to remember her life prior to the abduction. She is later found by two schoolgirls, Umika and Kaoru, whom she no longer recognizes as her best friends and roommates. As Kazumi attempts to readjust to her previous life, she quickly comes to understand that the life she once considered normal was not as it seemed.