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Negima! Magister Negi Magi, Vol. 28

Now that the tournament is over, Negi wants to find his missing students and take them home. But first, he’s confronted by a sinister man who claims to know the answers to all of Negi’s questions. He promises to share those answers—but only if Negi will join his cause.
 
Available on DVD from FUNimation Entertainment
 
Includes special extras after the story!