After retreating from Saitama during his fight with Orochi, Overgrown Rover continues to wander the Monster Association headquarters, until he comes across Bang, Bomb, and Fubuki.
Rover fires energy blasts at Bang, Bomb, and Fubuki. Fubuki shields them with a psychic barrier. The heroes dodge the multiple blasts and hide from the monster. The heroes are all stunned by the strength Overgrown Rover is displaying, with Fubuki panicking and stating that they should've stuck with King.
Suddenly, Overgrown Rover bursts through the wall and fires a point-blank blast. Bang and Bomb attempt to retaliate with their martial arts, but they are enveloped by the large blast, which destroys a large portion of the headquarters. The heroes emerge from the rubble, and the two martial artists are unharmed, surprising them. Fubuki reveals that she protected them with her barrier, although it was greatly taxing and caused her to ooze blood from her left eye and nose. Overgrown Rover stands over the heroes and prepares another attack. Fubuki laments how she cannot run and has failed the members of the Fubuki Group. She decides to sacrifice herself and tells the martial artists that she will put up her barrier one more time. The esper also informs them that she's reinforced their bodies, giving them a temporary boost in speed. Bang and Bomb note this and realize their lingering pains are gone.
The monster unleashes a barrage of energy blasts, which Fubuki tries to protect against with her barriers yet again. This time, however, Bang deflects the energy blasts with his Water Stream Rock Smashing Fist. As Fubuki stands shocked, Bang thanks the esper, and with his brother, they both lunge for Overgrown Rover. The two martial artists unleash the Cross Fang Dragon Slayer Fist, incapacitating the monster and sending him head-first into the rocks.
Bang and Bomb both high-five, while Fubuki nervously sweats, awestruck at the power they displayed and wondering if Bang actually has limits. This mentality extends towards Bomb, whom she realizes is just as strong as Bang is, and decides to extend an invitation to him while she still has the opportunity. The esper compliments Bomb and tells him that the special bonus for joining the Fubuki Group is a 3 kg special beef set. While she's giving this invitation, Overgrown Rover emerges from the rubble, appearing virtually unharmed. The heroes are all shocked, with Bang sarcastically asking why Rover couldn't just sit and behave. Having fought such strong opponents, Rover obeys the command, surprising the heroes yet again. Seeing that Rover is no longer a threat, the heroes decide to venture further into the headquarters. While they're leaving, Bomb is disappointed to see Rover having managed to withstand their special joint technique with no damage, stating that his confidence got crushed again after facing Elder Centipede. Bang asks what's wrong with Fubuki, and she says her back has given out.