Just a few years prior, automata served as weapons in the great war. Now that the war has ended, these machines with human hearts search for their place in an unfamiliar, peaceful world — and their search begins at the Kuronekotei café.

The national idol unit "Fool's End" suddenly announced its dissolution. The group will hand over the "Tenka Bata," which can only be held by the best idols in the world, to a successor group. The successor group will be decided based on the total score of each group's music sales, live attendance, and merchandise sales. The race was named the "Battle Royale for the Tenka Bata," and it marks the beginning of a nationwide battle of the idols. At the Kawanakajima Festival, where the three groups NO PRINCESS, Lunatic Eyes, and "X-UC" were to perform, an incident occurred to a member of X-UC. Umino Risa, the youngest member of X-UC, is so anxious about the high level of performance of the other idols that she runs away. As a result, X-UC will have to go on stage with the nine remaining members. Then the announcement is made that this Kawanakajima festival will be the first battle of the "Battle Royale for the Tenka Bata"!

Prince Wein is ready to commit treason. And who can blame him? Faced with the impossible task of ruling his pathetic little kingdom, this poor guy just can't catch a break! But with his brilliant idea of auctioning off his country, this lazy prince should be able to retire once and for all. Or that was the plan...until his treasonous schemes lead to disastrous consequences-namely, accidental victories and the favor of his people!

Yukina Minato gathers members intertwined with different thoughts to form a band and participate at the Future World Fes. This is the story of their "promise" from their formation to the challenge of the music festival.

Den City is a city with advanced network systems in which a VR space called LINK VRAINS was created by SOL Technologies. The Knights of Hanoi, a group that hacks through dueling, as well as SOL Technologies are seeking a mysterious AI program. Yusaku Fujiki, also known as Playmaker, is a first year high school student who manages to capture this AI program while trying to find out the truth about an incident in the past.