Synopsis
In 1999, an enormous meteor crashed onto Earth carrying extraterrestrial creatures known as Worm within it. These creatures took on the identities of real humans and then killed them. In order to counter this new threat, ZECT was formed, who in turn created the Masked Rider System to combat the Worms. The battles lasts over seven years, depleting Earth's resources and turning it into a barren wasteland. By present time, power struggles in ZECT have caused a new group, known as Neo-ZECT, to be created by Hidenori Oda. Neo-ZECT is an organization that does not wish to follow ZECT's orders, and fights for their freedom. Daisuke Kazama and Shura Hokuto are also part of Neo-ZECT.
With three groups in existence (Neo-ZECT, ZECT and the Worms), Souji Tendou has decided to sell his power to either Neo-ZECT or ZECT, but his intentions are unclear. At the same time, ZECT has obtained intelligence about a large comet orbiting the vicinity of space. By building the Jacob's Ladder space station, they plan to capture this comet and spread its water throughout Earth, replenishing the Earth’s oceans. The space station includes a function that works in conjunction with the Rider System's Clock Up function. Tendou joins Neo-ZECT after telling Kagami that he will act as an double agent and report back what Neo-ZECT is currently planning while destroying the organization from the inside. Tendou, in turns, updates Neo-ZECT about ZECT's operation, effectively manipulating both ZECT and Neo-ZECT against each other.
When Neo-ZECT's plan to take over the Jacob's Ladder is initiated, both groups’ true colors come to light. Tendou and Oda proceed to Jacob's Ladder while Shura and Daisuke act as a diversion. Daisuke transforms into Kamen Rider Drake and exploded a few gas tanks in order to gain attention. The plan failed when Shura betrayed them, and Daisuke realises it's a trap and ZECT already knows about their attack. Tendou and Oda are greeted by Yaguruma Sou and ZECTroopers, while Daisuke faces off against Shura and her troops. Taken by surprise, Daisuke collapses as hundreds of bullets pierce through his body, ending his life. "I just want...to be the wind..." are his last words.
Meanwhile, Tendou and Oda are attempting to fight off Yaguruma. Oda tells Tendou to hurry ahead to the space station, and he will hold Yaguruma and his troops back. Yaguruma transformed into Kamen Rider TheBee, while Oda transformed into Kamen Rider Hercus. and he is able to kill Yaguruma. Tendou arrived on Jacob's Ladder first and is confronted by Tetsuki Yamato - Kamen Rider Ketaros. After fighting Ketaros, they both fall off the space station due to the Clock Up function pulling through another meteor infested with Worms. This is ZECT's hidden plan.
Kabuto is able to survive thanks to the Kabuto Extender, but Ketaros dies upon re-entry into Earth's atmosphere. Tendou and Kagami receive news however, that Hiyori is on the point of dying due to the exposure to the meteor dust years ago and it is then that Tendou reveals he is Hiyori's brother. Holding the wedding ceremony in a hospital, Hiyori dies soon afterwards. At this point, Shura tells Tendou that ZECT has betrayed them and is allied with the Worms. ZECT plans to let the meteor crash onto Earth so that the Worms will conquer humanity. However, it seems that Caucasus and the leaders of ZECT are the only ones who know of this plan and attempted to silence her for overhearing their plans. Shura then dies from the wounds inflicted on her as Tendou and Kagami take it on as their mission to save humanity from this disaster.
Making it to the space shuttle in time, they meet Caucasus, who explains to them that the meteor is the medium to transfer Worms. The missiles within the shuttle will be used to destroy weak humans. Humanity will be taken over by the Worms because Caucasus believes he will protect and fight for the strongest and most beautiful, the belief of the rose. The majority of the battle is in Caucasus' favor; however when Caucasus activates Maximum Rider Power and prepares to kill Tendou with a Rider Kick, Kagami steps in the way and protects Tendou. Tendou is then able to use this time to steal the Hyper Zecter from Caucasus, forcing him into an ejection chamber and launching him into space. Tendou then puts Kagami back in an escape pod and sends him on his way back to Earth. However, Caucasus, while in the void of space, latches on to Kagami's escape pod and punches a hole into the window, killing Kagami. At the same time, Tendou becomes Hyper Kabuto and through the use of Hyper Clock Up, he reverses time to save Kagami and destroy Caucasus with a Rider Kick, blowing him up along with the missiles in the space shuttle.
Tendou then uses the Hyper Zecter's Hyper Clock Up to send the second meteor back in time and force it to crash into the first meteor. The result is a small fragment that only hits Shibuya, minimizing the damage and erasing the future in which the Earth's oceans are dried up. However, the shockwave caused by the two meteors crashing hits Tendou and sends him flying backwards towards Earth. Afterwards, Tendou lands in Shibuya and finds himself in the same situation he was in seven years ago. This time however, he gives his belt to the younger Tendou who is then able to save Hiyori. With the disastrous future erased, Tendou disappears as his younger self grows up and lives a better life in the new timeline.
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