"That's a different story" could suggest a less related subject Again, this difference is subtle For the most part the two expressions are interchangeable, especially for a nonnative speaker In actual usage, "that's another story" is more common but both are found in modern EnglishThe comic adaption of "Cheerfulverse The Different Story" is a humorous, sliceoflife spinoff that focuses on the daily lives of the Heroes of AlolaThe Different Story is a threevolume manga spinoff for the Madoka Magica Movie created by Hanokage The first volume begins as an adaptation of Drama CD 3, which details the events through which Mami and Kyouko meet for the first time and become witchhunting partners Ultimately, it culminates in an alternate timeline with a different outcome from the timelines
A Different Story Wikipedia