"Monster Strike The Movie" is an anime film adaptation of the popular mobile game "Monster Strike," blending fantasy, action, and adventure. The narrative centers on Ren Homura, a high school student who discovers a mysterious smartphone app called Monster Strike. Through this app, Ren is transported to a parallel world where monsters exist and are engaged in a fierce battle against the evil god Neter. Ren forms a bond with a dragon-like monster named Oragon, who becomes his companion and ally in the fight against Neter's forces.

The story unfolds as Ren and Oragon join forces with other monster partners, including Aoi Mizusawa and her monster companion, to protect both the human world and the monster realm from destruction. The group embarks on a journey to gather powerful orbs, which are essential to defeating Neter and restoring balance. Along the way, they encounter various challenges, including battles with formidable enemies and moral dilemmas that test their resolve and teamwork.

The film explores themes of friendship, courage, and the consequences of power, as Ren and his companions must confront their own fears and insecurities to succeed. The narrative builds toward a climactic showdown with Neter, where the characters' growth and unity are put to the ultimate test. The resolution ties together the fates of the human and monster worlds, emphasizing the interconnectedness of their struggles and the importance of cooperation in overcoming adversity.