Attack On Titan - Season 1 - Episode 15 - Special Operations Squad: Eve of the Counterattack, Part 2 [English Subbed]

Summary :- Eren joins the Special Operations Squad of the Scout Regiment and is taken to an old Scout base where they will prepare for the upcoming scouting mission. He meets his squadmates and learns of the Titan research performed by Section Commander Hange.
The next morning, the Scouts learn that Sawney and Beane, Hange's Titan test subjects, have been killed. As the Scouts wonder who is responsible, Commander Erwin asks Eren who the true enemy is.