Emu, a clumsy pediatrics intern takes young Sota, who is suffering a mysterious illness, to the announcement event of the latest "Mighty Action X", Sota's favorite game. Emu became a medical doctor in order to save someone's life because his life had been saved once through surgery.

However, a mysterious virus emerges from Sota's body and the event turns into chaos. Emu hears from Asuna, an employee of the Ministry of Health, that transforming into a Kamen Rider can save the patient. Emu takes on this "operation" and inserts the Mighty Action X Gashat into the Gamer Driver, transforming into Kamen Rider Ex-Aid!

Emu gives Kiriya another chance to earn his trust. Kiriya then takes the chance to finally reveal Kuroto's intentions and expose him as the Black Kamen Rider that is working with the Bugsters.

With Christmas around the corner, Emu runs against time to defeat the Salty Bugster again and save another patient, while Kiriya's investigation leads him closer to the truth, but his life is in danger when he faces Kuroto's new power.

Recently, Emu has been feeling a little worried. He is very quiet and hasn't talked much since Poppy Pipopapo suddenly disappeared. Just then, Hiiro is shocked by the sheer number of emergency calls coming to CR, all reports of the game illness! As the only CR doctors, Emu and Hiiro rush to the indicated locations, but what they find there is an unbelievable sight...

Kamen Rider Chronicle has already begun! Para-DX has joined the game and defeated the first round of the general players, giving them a Game Over as Emu watched them disappear before him. Kamen Rider Chronicle is being sold at an extremely fast rate, which catches the attention of the Ministry of Health. To avoid any form of confusion, Kyotaro Hinata orders a temporary halt on the actions of the doctors in CR. However, a game disease patient escapes from CR in an attempt to cure his own game disease, which leads Emu to chase after him. Then suddenly, Poppy Pipopapo appears before them with a new Driver and a Rider Gashat of her own…

Masamune Dan as Kamen Rider Cronus instantly killed Lovelica with his Pause attack, which freezes the game in time! The Bugsters and CR are greatly upset by Cronus' sudden appearance, Parado frozen in fear. Furthermore, it seems that the Proto Gashats being monitored by the Ministry of Health have been stolen by him! Now the doctors have been deprived of the data of the past Ride-Players. Emu goes to visit Masamune Dan, once again the CEO of Genm Corp. ...