Cardfight!! Vanguard Extra Story -if-

カードファイト!! ヴァンガード外伝 イフ-if-

The history of -IF- world has been distorted and cardfights do not exist. Ibuki and Suiko get involved with Emi and Shuka. A journey to regain the true history by four people begins—! (Source: Cardfight!! Vanguard Wiki)