Divine Era, year 298, two years before "Yuuki Yuuna's Chapter", Washio Sumi who was chosen by Shinju-sama, is a hero who protects the world alongside her classmates, Nogi Sonoko and Minowa Gin. It seems like Sonoko and Gin are trouble-makers because they could be idiotic or too energetic. Sumi is excited that she should lead the other two, but...

The WaSuYus haven't been able to unify because they haven't had much time to prepare. So, they decided to choose a leader and strengthen their unity by doing a training camp. Sumi saw herself as the leader, but Aki-sensei appointed Sonoko as the leader...

The WaSuYus now have stronger unity, are working hard to fulfill their roles as heroes. It's part of their job to rest as well. Three of them started to fully enjoy their momentary break.

The WaSuYus are going to their elementary school's class trip. The three of them are put in a crisis because of the Vertex's advanced action whom appeared as if to shatter their fun daily life.

The Hero's system advances to prepare for the battle with the escalating enemy. However, that was too brutal for the girls in 6th grade to have to bear. Nevertheless, the girls work hard to fulfill their roles.

Finally, the climactic battle has begun. The heroes are fulfilling their roles with full of new powers. The flowers bloomed beautifully. What kind of destiny would await them in the future...

Following their battle against the Vertex, YUuna, Fuu, Itsuki, and Karin are joined by a fully recovered Sonoko as the Hero Club resumes its normal activities. However, Yuuna starts to get a strange feeling that someone is missing from the equation. The next day, upon experiencing more deja vu, both Yuuna and Sonoko come to the realization that someone has altered their memories to make them forget all about Tougou, as if she never existed. Upon recalling their true memories of Tougou, who had been taking up a masked hero persona to make up for her sins, the girls are left with the question of where she has disappeared to.

Yuuna and the Hero Club work very hard.

Something surprising happens to the Hero Club again.

There was something written in a certain diary.

Yuuki Yuuna makes a major life decision.

Heroes' screams echoed out into the heavens.

The members of the Hero Club look forward to resuming their normal lives. And that means fun activities like band practice, karaoke, airsoft matches and camping trips!

Back in Divine Era Year 298, Taisha gathers a group of candidates. One of them will become the next hero, and Mebuki will ensure that it will be her.

The Sentinels have a dangerous task. Although Mebuki’s leadership has prevented fatalities, not everyone stays. Those who leave are replaced as if they were nothing but tools.

The Sentinels do not have the powers of a hero, but they have each other. When the Vertex unexpectedly attack, Mebuki and her team face a battle unlike anything before.

Sonoko’s family possessed The Hero Records for generations. When she entrusts it to the Hero Club, they learn about the first heroes who defended humanity against the Vertex.

People are cruel, a fact Chikage is all too well aware of.

Two friends with different perspectives arrive at a crossroads, and conflict is inevitable. And when conflict occurs, consequences follow.

What does it mean to be a hero? Wakaba and Yuna are about to find out.

Karin rages against the gods who cursed Yuuna, but they don’t answer when she issues a challenge from beyond the barrier. Instead, she finds the Sentinels and an old rival.

The Heroes begin their final mission, but they weren’t the only ones fighting that day. While they battled the enemy, the Sentinels were holding the line.

Tougou will do anything to save Yuuna, even if it means defying the will of the gods.

The battle is over at long last. Now, the Hero Club must ask what comes next.

Yuna Yuki, her best friend Mimori Togo, and sisters Fu and Itsuki Inubozaki, are all members of the Sanshu Middle School Hero Club, which is dedicated to helping those that request it via their website. During class one day, upon each receiving a strange 'forestize warning' message on their phones, the four girls find time has suddenly stopped around them before they are enveloped by a rainbow-colored light, soon finding themselves in a strange colorful forest.