Tales of Hearts follows main protagonist Kor Meteor after he discovers a woman named Kohaku Hearts and her brother Hisui near his home town. When Kohaku is attacked by a mysterious antagonist named Incarose and infected by a monster called a xerom, Kor attempts to cure her using his Soma, an ancient weapon designed to fight xerom. In the process, he ends up shattering Kohaku's Spiria, the essence of her heart and emotions, and scattering the pieces across the world. Together with Hisui, Kor sets off with Kohaku on a quest to restore her Spiria.

(Source: Wikipedia)