S2E7 · Chapter Seven: The Lost Sister

Complete story — includes the ending

Eleven travels to Chicago, Illinois, and finds the other girl from Terry's memories, named Kali. Realizing they have similar tattoos and were both experimented on by Brenner, Eleven and Kali consider themselves sisters. Kali can project images into people's minds and leads a street gang to seek revenge on Brenner. Eleven tells them that Brenner is dead, so the gang decide to kill the man who tortured Terry instead. Kali helps Eleven hone her abilities by demonstrating that channeling her anger is the key to strengthening her powers. After Eleven uses her powers to find the gang's target, named Ray, the gang travel to Ray's apartment to kill him. Eleven begins to choke Ray with her powers, leading him to reveal that Brenner is still alive. Eleven refuses to kill Ray after seeing a photo of his two young daughters, who are discovered at that same moment to be contacting the police. Eleven stops Kali from killing Ray. The gang flees to the hideout, and Kali insists Eleven either stay and avenge her mother or return to Hawkins. Eleven has a vision of Mike and Hopper's plight at the lab and decides to return while Kali and her gang escape from the police.