Jun Terada is a producer in the year 2076 and is trying to convince the president of Magical TV to allow her to create her life's work, Cho Ninja Tai Inazuma!, based on the long-standing legend of a legendary lightning that bestows powers upon those struck by it.
President Mishima convinces her to turn it into a reality show by traveling back to 1720 in the Edo period and picking three extremely inept locals and force them through humiliating training to become ninja.
When Jun and her writing partner Kuratanomiya arrive in the past, they find Hosomatsu, Kankichi, and Kaguya, three extremely cowardly, inept, and clumsy individuals, to be the stars of their show.
But learning that the legendary lightning exists, Jun discovers that it's the spark from the glitches in the time teleport system that created the monster slugs.
With that knowledge, Jun sends Kuratanomiya back to the future so she can become an antenna for the legendary lightning and empower the Inazuma team before they are killed by the three monsters.
A year after the prequel's events, Jun is now producing a sequel to her original show and has the daughter of Magical TV's president as her female lead.