Kai relates the story of his struggle to Nima who possessed by demon sprit after she become as a demon queen at the her castle where he is housed and neglected. kai story begins 60 years earlier when he is quite his jobs after his girlfriend who is killed by hulk and kai is hired by his cousin and her police men. Eventually, female cop teaches kai to train correctly but his cousin is taken away by a villain named el macho because he believes the gru's daughter cannot distinguish fantasy from reality because she believes the ninja can have a powerful. kai goes through a series of adventures to find an antidote for angela with a Bagges family, an ageing widow, a Mexican troubadour and a would be thief before being taken to the institute where he now lives.
The prologue begin, Kai's cousin, Kate rose who is kidnapped by Villain who imprisond her.
The movie film begin, an old kai and his long quest to bring back his lover to life.
Nima cruz, who is now possessed by demon and lives in Her castle and absorb all parents life sources as a a evil queen at the earth. At her castles, Nima encounters Kai in last time and is shocked to see Kai is staying the island. Subsequently, Kai does not remember his memory when Nima brings others to witness the amnesia ninja. Nima woos Kai to tell his story by offering him pieces of apple. Kai tells Nima about his love interest, Angela William G. Dragson who was a killed by monster. The story transitions to a flashback scene in which Kai is a 37 years old, he quite his jobs and goes work at police. As Kate learns to speak, so does Kai, beginning with understanding the meaning of rule and progressing to the construction of complex sentences. the owner of Salsa & Salsa, a Mexican restaurant and decides that Kai is not helping Kate. El macho's resentment of the close bond between Kai and Kate, and their shared progress in speech development is evident.
It becomes obvious that he wants Kate to forget Kai, when el macho brings her a giant swamp rat. The rat and Kai don't get along, because the rat has diseases. Once again, El macho blames Kai for Kate's training problems and believes she has imagined Kai's ability to train. Eventually after a dramatic event in which Kate falls off the roof in an attempt to teach Kai to ride a boat, Kai convinces El macho's son, Antonio Pérez, to send him away.
Kai is passed from one owner to another, eventually ending up in a police jail, where he spends his time insulting the person until he is releasesed by a widowed artist named helen jackson. She befriends the ninja and agrees to find Antidote to save Angela, who has moved across the country to Los Angeles. Helen loses her sight and Kai decides to stay and take care of her. After Helen dies, Kai, having finally learned to rowing a boat with a map, continues his journey, Years pass in 2020.
In East Mexican, Kai joins a group of performing female Mexican owned by A man named James jones, but later begins a life of crime after being kidnapped by Scarlet overkill. In a botched jewel theft and greatest villain, Kai sneek down through the chimney of anti villain, gru's house, where he is trapped inside, then abandoned by gru's adoptive Three daughters.
Kai is then brought to the institute, his current home, where El macho's employees and scientists are stunned by his intelligence. They subject him to testing, and promise that he will be reunited with Angela. When Kai discovers that he has been lied to by way of his acquisition as institute property, he refuses to cooperate with any more tests. As a result, Kate who escape by jack save Kai who escaped from el macho's lair into his boat, jack's body are chopped by el macho pet chicken,Pollito, kate is imprisoned in the dungeon and Kai accidentally land on survival island.
Moved by Kai's story, nima decides to give up her menial job to release and take him to Angela. After escaping from the institute to save Kate, Kai repeated warnings that he will die by el macho who defeat by Nima, unless he goes back to the hospital, saying he must get in his last words to his friends. Kai reaches his friends and collapses, but manages to convince Mae that family comes first; he reassures the rest that he still loves them (including Himself, much to his surprise) and Harding comes up to take him, There is a white flash, in which Kai wakes up in the present day on the bed And taking a bus to her flower shop, they find her, now a full survive, from the nightmare unrecognizable to Kai. After a moment of confusion, Kai and Angela are happily reunited as Angela sings her favorite song called lullaby and he remembers her. The film ends with the all characters happily entering the party with Kate and jack.
Epilogue, in post credit scene, Umbra who imprisoned by Nima who escaped from her possession power, now full power with Aaron.