History Strongest Disciple Again?

Time Travel Fic! When the missile detonates prematurely at Yami's base of operation during the invasion to prevent the Eternal Setting Sun, all hope seems lost... Until Niijima somehow rips a portal to the past that sucks Miu, Kenichi and himself in. Now armed with that knowledge, the trio must work together to change the future! First-time travel fic in Kenichi universe I think!