WARNING: The following contains spoilers for My Hero Academia, Episode 70: Go!!
The last episode of My Hero Academia revealed the terrible secret behind the villain Overhaul's assault on the hero community. Overhaul's daughter, Eri, is able to damage the quirks of heroes she comes into contact with, which Overhaul has utilized as a weapon. Using his own quirk, he is able to disassemble and reassemble anything he comes in contact with, including the flesh of his own daughter, and channel it into the pinheads of darts.
Now, confronted with the real depths of human depravity Overhaul is willing to reach, both Midoriya and Togata must fulfill their heroic duties by helping the girl in need so that she might never suffer again.
THE CALM BEFORE THE STORM
Episode 70 starts with the young students, who are between school and work study, on standby in case Sir Nighteye needs them. However, they're told to keep everything silent, which is made difficult by their classmates asking questions about what they've experienced. Midoriya, Uraraka, Kirishima, and Tsuyu are encouraged to remain minimally involved, despite them eagerly wanting to help. After all, with the League of Villains teaming up with the yakuza, things will be dangerous, even for pro-heroes. The young heroes' goal, for now, is just to rescue Eri.
This pressure piles onto Midoriya's conflicted feelings over knowing All Might's fate. With the guilt of letting Eri go and the knowledge of his mentor's doomed destiny, he's acting very odd -- odd enough for classmates like Tenya and Todoroki to worry about him. Even the smallest gesture of kindness is enough to make Midoriya start sobbing.
FINDING THE TARGET
At the same time, Rock Lock, Fat Gum, Ryukyu and the various pro heroes under Sir Nighteye set off throughout Japan to investigate key locations belonging to Overhaul to find Eri or other information relating to the operations. Days pass with the students hearing nothing from the investigations, as each lead turns out to be a dead end.
Eventually, Midoriya, his classmates and the Big Three -- Mirio, Nejire and Tamaki -- are called in the middle of the night to prepare after learning that Eri is being kept inside Overhaul's home. They found this out because one of Overhaul's henchmen bought a ton of merchandise for young girls. When there, Nighteye used his quirk to see the lackey's entire future, which confirmed Eri was in the base. With a warrant to barge in, they prepare to launch an attack on the base.
At 8 A.M, the police assemble outside the yakuza group's base. They don't have a full map of it, but they determine the man took the shortest route to Eri and they have a list of the crime syndicate's soldiers and their quirks. Everyone is in attendance, save for Gran Torino, who is investigating the League particularly. To further complicate matters, Eraser Head has teamed up with Sir Nighteye in order to keep an eye on Midoriya.
At the same time, Overhaul visits his father, in his hospital bed, apologizing for the coming mess.
THE FIRST STRIKE
Right as the police ring the bell to commence the attack, a villain tries to punch his way through the front door. The yakuza adversary starts beating police officers aside en masse, but they fail to get far as Ryukyu turns into a dragon and just holds the assailant down.
The police charge forward with their warrant and the outside security is held down and suppressed, allowing the heroes to charge straight through the front door with Midoriya and Togata first among them -- ready to save Eri once and for all.
As the charge starts upstairs, however, Overhaul begins to figure out how to escape in My Hero Academia's next episode; sending out eight primary underlings to intercept the heroes and buy himself some time.