Unless I Die, the Song Dynasty Will Not Perish

A history college student died suddenly because he stayed up late memorizing information. He traveled to the day when the Song Dynasty was destroyed and became the last member of the royal family. That day on Yashan: Lu Xiufu jumped into the sea in betrayal of the emperor, Zhang Shijie broke out of the siege and was caught in the wind, with hundreds of thousands of corpses floating on the mountain, and the Southern Song Dynasty was destroyed?