Part 1 of “Making a Murderer” presented the conviction, exoneration, and second conviction of Steven Avery — as well as the conviction of his nephew, Brendan Dassey — for the murder of Teresa Halbach. Part 2 of Laura Ricciardi and Moira Demos’ true crime docuseries will focus on the renewed legal efforts to exonerate the men, a grass roots movement galvanized by Part 1. A new trailer for the Netflix phenom’s sophomore season has dropped, and it centers on Kathleen Zellner, a new lawyer on the case — and one with the reputation of overturning wrongful convictions.

“I have one goal, and that’s to overturn the conviction of Steven Avery,” Zellner announces in the spot. In order to meet that goal, she’ll look into the ballistics of the original crime and Halbach’s location before she died. The prosecution maintains Halbach never left the Avery property, but cell phone records show she made her last call miles away.

Zellner is confident in the case and in her client’s innocence. “If he’s guilty, I’ll fail,” she says.

Ricciardi and Demos won Emmys for directing and writing “Making a Murderer” Part 1, and Demos took home another statuette for editing. The show also received the award for best documentary or nonfiction series.

Part 2 of “Making a Murderer” drops on Netflix October 19.