Ghost of Tsushima starts with disaster striking. Tsushima Island is under attack from the Mongols being led by Khotun Khan and the battle is one the samurai of the island are not prepared for. The Mongols have been studying their ways, and they know how to use their code of honor against them. Fortunately, Jin Sakai is around, and he is prepared to learn new forms of combat to drive off the Mongols.