The Sisters Who Have Too Many Things Happening

Iroiro Ari-sugiru Shimai (色々ありすぎる姉妹)

During the Seafolk invasion, the Blizzard Group get rid of one of Deep Sea King's henchman. They are disheartened to learn that their heroism didn't make in the next day's newspaper, while everyone else's did. Fubuki takes this the hardest, and decides to go on a train ride to Z-City to clear her thoughts. Genos, happens to also be on the same train on his way home with groceries. Later during their ride, Genos receives a call that an ex-Hero Serial Bomber planted a bomb on the train and that it will detonate once it reaches the train station.

Fubuki evacuates the panicked civilians off the train while enlisting the help of a budding new hero, Swim, to find the bomb, while Genos tries to slow down the train from the outside. As Fubuki evacuates Swim, she hesitates while thinking about what to do with the bomb. Tatsumaki appears and successfully allows the train to detonate with no casualties. Fubuki once again expresses envy towards her older sister's actions. On the walk back, Fubuki meets up with Swim, who expresses gratitude for Fubuki's actions, and wishes to join Fubuki's group once she reaches B-Class. Meanwhile Genos visits Dr. Kuseno asking for psychic augmentation, to which the doctor denied, since it's not possible. The OVA ends with Saitama wondering why Genos is so late.