Kamen Rider ZO

Masaru Aso is the laboratory assistant of geneticist Doctor Mochizuki, and he is used in one of Mochizuki's experiments related to the creation of the Neo-Lifeform. The process enables him to transform into the grasshopper-like Kamen Rider ZO. The experiment marks the origin of his dual life as a protector and a bio-engineered weapon.

Masaru escapes to the mountains, fleeing Mochizuki's project and the life it entails. He lapses into a coma that lasts two years, during which he remains cut off from the outside world. The long sleep leaves him vulnerable to whatever danger lies ahead when he awakens.

Masaru awakens to a telepathic call urging him to protect Hiroshi Mochizuki, the doctor's son. Feeling the danger closing in, he shifts into ZO and rescues Hiroshi from a Doras attack. The rescue occurs near the Mochizuki Genetics vicinity, underscoring the bond between Masaru and Hiroshi.

Doras regenerates from the previous battle and spawns two new creations to hunt Hiroshi. The dual threats, Spider-Woman and Bat-Man, intensify the danger surrounding Hiroshi. Masaru's protective mission expands as new foes enter the scene.

In Seikichi's vicinity, Hiroshi seeks help and Masaru reveals himself to Reiko and her karate class as Hiroshi's bodyguard. A freak bat attack erupts, and Bat-Man crashes into the action after being knocked out of the air by one of the students. The confrontation sets the stage for ZO's next appearance.

Masaru, now in ZO form, fights Bat-Man to cover Hiroshi and Reiko's escape. Spider-Woman intervenes and pulls the group into a pocket dimension, separating them from the world above. The battle shifts to a surreal, enclosed space where danger intensifies.

Inside the pocket dimension, ZO defeats Spider-Woman and frees the group from her grasp. Bat-Man makes another bid to kidnap Hiroshi but is thwarted by ZO's timely intervention. The trio escapes the immediate threat and prepares to regroup.

Back outside, Masaru shares with Seikichi that Hiroshi's father used him in his experiments. Seikichi's initial skepticism gives way to uneasy acceptance as the truth sinks in. The revelation reshapes Hiroshi's understanding of his family and his own fate.

Hiroshi runs off after the troubling revelation, and Masaru tracks him down. He fixes Hiroshi's keepsake watch, and the melody associated with it helps awaken memories and provides comfort amid the shock. The moment deepens the bond between protector and ward.

In a crowded city, Hiroshi spots his father alive and confronts him, only to have his father reveal himself as Bat-Man in disguise. The confrontation shakes Hiroshi and tests Masaru's ability to shield him from the truth. The city setting heightens the stakes of their revelation.

Dorans strike with brutal force and knock Masaru unconscious, sending him plunging to the ground. He regains consciousness when a grasshopper guides him to Hiroshi's location. Renewed determination pushes him toward the complex to resolve the looming crisis.

ZO arrives at the complex and confronts Bat-Man, ultimately killing him. He then finds Hiroshi and Mochizuki and learns that Mochizuki was the one who woke him up. The revelation ties the mission directly to Mochizuki's experiments and motives.

The Neo-Lifeform fully materializes from a pool and seizes Hiroshi's voice to reveal its plan: use Hiroshi to complete the professor's work. It morphs into Doras to fight ZO, and then absorbs ZO into its body to become Red Doras. The fusion marks the ultimate escalation of the threat.

Hiroshi's keepsake watch emits a haunting melody that holds Doras at bay just long enough. Mochizuki sacrifices his life to damage the Neo-Lifeform's pool, weakening the fusion and allowing ZO to break free. The sacrifice highlights the stakes of their battle and the price of victory.

With a decisive Rider Kick, ZO defeats Doras and destroys the Neo-Lifeform. The complex begins to self-destruct, forcing a desperate escape with Hiroshi. Masaru leaves for parts unknown, entrusting Hiroshi to Seikichi as the two part ways.