Chapter 24

A surviving researcher fills Shin and Taro Sakamoto in on how the Okutabi Lab fell: six days earlier, a band of assassins seized the building. In a flashback, their leader Kashima announces that his crew wants cutting-edge killing tools and intends to help itself to the scientists' minds. The invaders, split into suited squads with a boss assigned to each floor, have effectively taken the place over. Shin reasons that tracking down Lu will likely mean fighting through them, and the panicked researcher stuffs the pair into lockers as an approaching patrol nears.

The boss who arrives is Mad Horiguchi, curious about the noise and unconvinced by the scientist's denials. He drives a pen into his own hand and presses about the unconscious underlings left outside, brushing off a pen Shin flings at him from hiding. Asked why he stepped out, he shrugs that he simply dislikes cramped spaces. When Shin questions whether he runs the floor, Horiguchi turns menacing and jabs him with an electrode that scrambles his nerve signals, a device controlled by a remote hidden along his sleeve. He rewires Shin's speech so every word comes out backward.

Sakamoto finally forces his way out of the locker and lands a punch on Horiguchi, telling Shin that his own past with this lab runs deep and asking if the young assassin will help him save it. The two commit to driving the raiders out. Rising to his feet, Horiguchi says he would relish studying Sakamoto and notes how frail his target looks. He has already slipped an electrode into Sakamoto too, and when Sakamoto swings, Horiguchi hijacks the brain's targeting so the blow strikes Shin instead. Delighted, Horiguchi crows about the wonders of science, but Sakamoto adapts, aiming at Shin so the redirected punch finally connects with Horiguchi.

Shin and Sakamoto learn that assassins under Kashima have occupied the lab to steal research on new killing tools. Mad Horiguchi, the floor boss, makes his debut and reveals his signature trick: electrodes that hijack the nervous system, forcing Shin to speak in reverse and redirecting Sakamoto's punches onto his own ally. Sakamoto counters by deliberately aiming at Shin so the hijacked strike lands on Horiguchi, and he and Shin resolve to retake the lab.

This chapter carries the title Assassins x Science, or Koroshiya x Kagaku, and is the 24th installment of the series, collected in Volume 3 during the Lab Arc. It spans nineteen pages and was published on May 24, 2021 in issue 25 of that year. The cover assembles a large group including Sakamoto, Shin, Lu Shaotang, Shishiba, Osaragi, Seba, Tanaka, Asakura, and Kashima. It follows Chapter 23 and leads into Chapter 25.