Ken Sato is a superstar baseball player who returns to Japan to become the latest hero to carry the mantle of Ultraman. However, he is compelled to raise a newborn kaiju monster, the offspring of his greatest enemy, as his own child.
Ken Sato, a superstar baseball player who returns to Japan to become the latest hero to carry the mantle of Ultraman. His plans go awry, however, when he is compelled to raise a newborn kaiju monster the offspring of his greatest enemy as his own child. Sato will also have to contend with his relationship with his estranged father and the schemes of the Kaiju Defense Force.
Ultraman has protected humans from Kaijus for over 30 years. Kaijus are not the villains, but not exactly heroes either. Mina is Ultraman's AI assistant. Professor Sato is the original Ultraman and trains his son Kenji to take over the mantle from him when he retires. Sato says that the most important thing is to find the balance between the Kaijus and the humans. Kenji is very connected to his mother Emiko.As a kid, Kenji watches his father battle Kaiji Gigantron, as Ultraman.
20 years later, Kenji "Ken" Sato (Yuki Yamada), is a professional but egotistical baseball player. Kenji returns to his native home in Japan, despite being on the verge of a championship win in America. Reporter Ami Wakita (Akari Hayami) attributes his sudden departure to rumored unfinished family business. Kenji has a 420-batting average and 624 stolen bases. Ami says that Kenji's ego is holding him back from winning championships.
But secretly, Ken is returning to Japan to battle Kaiju (giant monsters) as the giant superhero Ultraman, a mantle he reluctantly accepts from his father, Professor Sato (Fumiyo Kohinata). Kenji joins the local baseball team in Japan to have a cover for his identity as Ultraman. Coach Shimura (Nan Dadian) is not happy that Kenji is away from practice for extended periods of time. Shimura detests the lack of humility in Kenji.After a battle with the monster Neronga (kind of like an electric Armadillo), Ken feels under-appreciated after citizen complaints. Kanji leaves the battle mid-way when the Kaiju Defense Force arrives and brings Neronga under control. Sato tells Kenji to go back and battle the Kaiju and talks about his responsibility as Ultraman.Ken vents that he never wanted to become Ultraman and reminisces about his mother Emiko (Ayumi Tsunematsu), who's gone missing recently. There have been no sightings or readings from her GPS locator.
Dr. Onda (Fumihiko Tachiki), Chief Officer of the Kaiju Defense Force (KDF) who harbors a grudge against Ultraman and Kaiju. Onda and the KDF do not consider Ultraman as an authorized Government agent. Onda and every member of the KDF has experienced the loss of a family member to the attacks from Kaijus.He monitors a transport team delivering a secret package to the KDF HQ in Tokyo. However, they are pursued by the winged bird-like Kaiju Gigantron. The KDF team is attacked by the Kaiju just outside the stadium where Kenji is playing his first game. Ken is forced to abandon a game and battle the beast. Onda sends all his combat jets to kill Gigantron. Ultraman tries to save Gigantron as it hit by KDF missiles, as Gigantron tries to protect the package. They all go down into the ocean.Gigantron loses consciousness on top of the package, which is revealed to be an egg. An infant Gigantron soon hatches, forcing Ultraman to take her with him before the KDF kill her.
The baby imprints on Ultraman as her parent. But when Ultraman changes into Kenji, the baby Kaiju is afraid of him. The baby's cries are an ultrasonic frequency that create havoc. With the help of his A.I. assistant Mina (Ayumi Tsunematsu), Ken reluctantly raises the baby, named Emi after Ken's mother. Unwilling to accept his father's help due to their estranged relationship, Ken struggles with his career and parental duties. Kenji accuses Sato of picking Kaijus over his own family. He says that Sato got old and left his mess for Kenji to clean and Kenji had to come back as his mother begged him to.Kenji wants to take the baby Kaiju to Kaiju Island, but no one has ever seen it.
Meanwhile, Kenji convinces the infant that he and Ultraman are the same. He has no idea what to feed the baby. The infant Echo-locates fish and that's how Kenji finds out what to feed her. Mina realizes that till the time they find Kaiju Island, they will have to raise the baby.By Day 71, Kenji is exhausted trying to balance the baby and his professional commitments. As a result, his performance in the games goes down. Kenji Sato is slated to be traded to another team, mid-season by his coach.He reaches out to Ami, a parent herself, and asks how she deals with parenthood. She acknowledges that it's not easy but can be rewarding and surprising. Over time, Ken grows emotionally attached to Emi and teaches her how to play baseball.Meanwhile, Onda and the KDF are frantically searching for the infant Gigantron Emi.
One night, Ken drops out of an interview with Ami due to Emi escaping and running around Tokyo. Recognizing Emi as the missing asset, Onda demands Ultraman to hand her over. Ultraman refuses and accidentally injures Emi's shoulder while trying to save her. He escapes with Emi to his home and finally contacts his father for help. Sato succeeds in healing Emi and aides Ken in raising the baby.
Onda reveals to the KDF's Captain his plan to exploit Emi's Echolocation to find the undiscovered Kaiju Island and destroy all monsters. Onda says that eventually the infant would want to go home, and all they need to do is follow. Onda justifies this as a means to an end to protect humanity, after his family perished during a Kaiju/Ultraman incident.Onda declares to the media that Ultraman is protecting a Kaiju infant and turns the public against him.At a family cabin, Ken and Sato reconcile their relationship, now that Ken understands the struggle of being both a parent and Ultraman. Together they teach Emi how to survive, by teaching her how to fish, and how to run and fight from predators. As Kanji gets more mature, his performance on the field improves and his team starts winning games. Sato tells Kenji that being Ultraman is not about fighting but using his powers to bring balance between humans and Kaijus.However, Emi enters a pupal stage as the KDF find and attack them, injuring Sato. Ken places his father in a healing tube back home and Emi hatches from her cocoon, now sporting wings. She hears the calls of her birth mother across Tokyo Bay and flies towards her. Turns out it was not Emi's mother but a mechanized Gigantron, controlled by Onda.
The KDF soon attack Ken's home, destroying Mina and his father's tube disappearing into the sea. Ultraman tracks Emi to the middle of the Bay where they both encounter a mechanized Gigantron. Ultraman attacks it but stops when he notices flesh beneath the metal, realizing it's not a machine but the original, still alive, with armor plating.However, Ultraman exceeds his energy and reverts to Ken but is saved by his father in Ultra form, Ultradad. Emi manages to break the KDF's control over Gigantron. Onda transforms a KDF craft into a giant Mecha and battles the two Ultras and Kaiju, blaming Ultradad for the death of his family. Onda is defeated but triggers a self-destruct sequence. Ultraman forms a barrier encircling him and the Mecha; Onda watches videos of his family one last time before the detonation.
Later, Ami finally interviews Ken, having survived and now sporting an injured shoulder. Ami notes that Ken has matured recently and Ken attributes it to his family. He shares a voicemail from his mother that expresses her hopes of Ken reconciling with his father and that their decisions as parents came from a place of love to prepare him for life. Ken and Sato succeed in finding Kaiju Island, with the help of Emi and Gigantron.
In a mid-credits scene, Emiko contacts Ken for help, revealing that she is stuck on Ultraman's home planet Nebula M78.
