One day, the boy Yanlian returned to the city "Kamihara" where he used to live. Although he walked on the familiar streets, he felt an unknown sense of disharmony and could not recall his past memories... Suddenly, Yan's mobile phone was forced to install the unknown game "Monster Strike", and various monsters flew out of it to fight. With the development of the super dimension, Yan vaguely discovered that the secret hidden deep in his memory is the key to everything. With the help of his partners and monsters, will the door to reality open to him?