The prophecy narrated by Yoshida in Chapter 122 of Chainsaw Man led to the coming of the First Primal Devila dangerous new villain who could end the lives of Asa Mitaka and the Devil War Yoru.
In Chainsaw Man 122, Yoru sensed the danger and went on the run. This is the evil that has come into the world falling devil, a devil whose power is to exploit people's fears to bring them down spiritually. The falling devil is therefore able to manipulate past trauma to drive any person to suicide.
While Yoru is also on the run from the devil Asa falls victim to this power. Through a flashback we find a young Asa dealing with everyday life in the orphanage where she ended up after her mother died at the hands of the devil Typhon. The girl had no friends and the only companion she could rely on was the little cat she rescued on the day her mother died. However, the caretaker of the orphanage persuaded her to do so Separation from Crambon, promised to take care of it for her. The caretaker lied and killed the cat because Asa couldn't have a family while all the other orphans didn't.
Back to the present Asa almost falls into space due to the power of the falling devil. However, the girl manages to hold on to the ground, even though the War Devil is no longer able to take control of her body. How will she survive this dangerous situation?