Princess Principal/Recap/S1/E06 Case 16 Loudly Laundry

Quoting from Wikipedia: "The team is tasked with tracking down a serial killer dubbed "Poison Gas Jack", who is using nerve gas to assassinate people who are sympathetic to the Commonwealth. They surmise that the killer is a soldier stationed at a base that stores stocks of nerve gas. Knowing that they can find the killer by finding nerve gas residue on his clothes, the team infiltrates the local laundry mill that services the base, but quickly find that efficiency is poor due to poorly maintained equipment and sloppy layout. In addition, the laundry mill is deeply in debt and on the verge of closing, threatening the mission. Princess decides to purchase the laundry mill and its debt, and the team goes about fixing and rearranging the machinery, which vastly increases efficiency and productivity. Meanwhile, the killer's uniform is inadvertently sent to the laundry mill, and he heads there to recover it. Princess finds his uniform and discovers his true identity, while Chise knocks him out. With their mission done, Princess steps down as the laundry mill's foreman and promotes Marilla, the most veteran laundry mill worker, to take her place. Despite leaving, the team is confident that the laundry mill workers will be able to take care of themselves from now on."