The second episode of Heroes Season 3 will comprise the second hour of the show’s premiere, which airs on September 22.

It's called "The Butterfly Effect" and here's NBC's official plot summary for it:

In the shocking second chapter of “Volume 3: Villains,” Angela (Cristine Rose) clashes with her much-changed son, Peter (Milo Ventimiglia), over how best to avert a seemingly inevitable worldwide catastrophe. First, Sylar (Zachary Quinto) declares war on the Company by attacking their main facility, and finds even more than he bargained for on Level 5.

During a devastating battle with Elle (guest star Kristen Bell), a dozen savage criminals — all with terrible abilities — escape. Meanwhile, Claire (Hayden Panettiere) discovers something new and unexpected about her abilities. Determined to reclaim his family’s terrible secret, Hiro (Masi Oka) and Ando (James Kyson Lee) track Daphne (guest star Brea Grant) to Paris.

After a fateful night, Suresh (Sendhil Ramamurthy) is thrilled to find his research, his life and his relationship with Maya (Dania Ramirez) evolving in leaps and bounds. Stuck in unfamiliar territory, Matt (Greg Grunberg) finds a guide (guest star Ntare Mwine) to help him.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.