Terumi has no memory of her life leading up to when she nearly drowned as a child in her town's local lake, Lake Shoryu. Terumi has been supported by her family and her close childhood friend Yukio since that time, although her family also does not seem to understand the reason for this childhood incident. 12 years later, Terumi finally decides to leave her town for a new job, but before doing so, begins investigating the drowning incident together with Yukio in order to know the truth. During her investigations, Terumi meets a man named Soda, who seems to have the same experience of nearly drowning and recovering with no memory as she does. As she digs deeper, a strange relationship between her and the legend of Lake Shoryu begins to surface.
Ahead of No. 1 Sentai Gozyuger's premiere, in a conference room somewhere, Gokai Red, Zenkaizer, Kamen Rider Decade, Kamen Rider Legend, and Gozyu Wolf are sitting in a discussion table. They are engaged in a heated debate about whether Gozyuger should be recognized as an anniversary. What will be the outcome?!
When a Karizaki from a parallel Earth arrives and asks for the Riders' help, Daiji, Kagerou, Hiromi and Vice argue which of them is Ikki's secondary rider.
Taking place after the events of the Kamen Rider Gotchard TV series, the time is approaching for each of them to leave for their individual tomorrows. After graduating from high school, Houtaro Ichinose's dream remains the same: to become a big-time alchemist. Renge Icho and Sabimaru Tsuruhara are also moving on to the next stage. As for Rinne Kudo...