While in Zawame's Free Performance Zone, Mai and Mitsuzane of the dance team Team Gaim are having a free-spirited dance when members of rival Team Baron scare them away when an Inves Game gets out of hand. When Mai goes to former teammate Kouta Kazuraba to reveal something strange has happened, he reveals that Team Gaim's leader Yuya gave him a strange Lockseed, and Mai reveals Yuuya informed her of it as well. The two eventually find a way into the Helheim Forest that has appeared in the Free Performance Zone.

Kouta tries to use his new abilities as Kamen Rider Gaim to help out at his part-time job, but he only gets in the way. And when Yuuya mysteriously disappears, Kouta wonders if what happened in the forest was real, and now that he is in charge of Team Gaim, he must lead the group in a dance-off against Team Baron.

Kouta tries to overcome the events that befell him in the Helheim Forest against Zangetsu while Kaito challenges Mitsuzane to a fight, with the new Armored Rider Ryugen unable to fight Baron on his own.

Hase and Jonouchi transform into Armored Riders Kurokage and Gridon, but something strange happens during their fight with Baron against Gaim and Ryugen. Later, Kouta tries to get a part-time job at a pastry shop, only to be disturbed by the effeminate head chef.

After easily defeating both Kurokage and Gridon, Kamen Rider Bravo steals their Lockseeds and sets his sights on defeating all of the Armored Riders. Kouta is angered that Oren has made it his mission to defeat all of the Armored Riders, but Kaito just tells him to beat him to get it over with. Before long, Bravo issues a challenge to Baron, but it is not Baron who he is really after.

Kouta and Mitsuzane must hunt down a fully manifested Inves that is randomly attacking people in the city while also dealing with keeping up their Beat Rider ranking.

A mysterious bacteria is infecting people in Zawame City. In the crisis situation, Kouta, Mai, and Mitsuzane try to find out the cause behind this.

After Hase transforms into an Inves, Gaim tries to take him out before he can do much damage but finds it difficult to harm someone who he believes is still human inside. Meanwhile, Baron does his best to combat Zangetsu Shin but is overcome by Kurokage Troopers and captured. And Mitsuzane, who realizes his brother is their foe the white Armored Rider, infiltrates the Yggdrasill Corporation headquarters on his own to see what is truly going on.

After escaping the clutches of the Yggdrasill Corporation, Kouta wonders why all three of them were able to escape so easily, knowing how Ryoma Sengoku was interested in them. Later, Mai and Chucky continue to try to convince other teams to end the Inves Game, but they instead witness an Elementary Inves robbing a jewelry store. Meanwhile, Takatora has shown Mitsuzane a horrible scene hidden within the Helheim Forest and revealed that he easily beat Kouta.

Now aware that he killed Yuya, Kouta loses all will to fight, and will not even seek to destroy the Scalar System. As he struggles with the thought of telling the truth to his friends, Kaito encounters the strange Inves in Helheim Forest, once more.

After watching Kouta, Mitsuzane, and Zack battle Inves, Jonouchi realizes that the dance team days are over, again. Later, Oren arrives to begin Jonouchi's next set of training. Kaito tries to tell Kouta about the Over Lords, while DJ Sagara is confronted by Ryoma, Yoko, and Sid. After Gaim, Bravo and Gridon fought the Inves that appeared Oren and Jonouichi goes home but Jonouichi reveals to Oren that the Inves Game is no more. Later, Oren finds a crack and tries to investigate it but discovers something yet to be revealed.

Mai wants to know why Kouta has been hiding from her, and he reveals the truth to her about Helheim Forest, as well as the Inves and the fate of Yuya, upsetting Mitsuzane, who is still under orders from his brother. Meanwhile, Kaito plans to finish his fight with Demushu.

Betting their lives and beliefs, Kazuraba and Kaito finally face off.