Strange Attractors

T4, E7: Matt (Greg Grunberg) goes to extreme measures to extinguish Sylar (Zachary Quinto), who continues to torment him. Elsewhere, H.R.G. (Jack Coleman) calls in a favor from Tracy (Ali Larter) to save a troubled young boy whose misfortunes resemble her own. While Claire (Hayden Panettiere) and Gretchen (guest star Madeline Zima) are being hazed by their new sorority sisters, they realize pledging might not be their biggest problem. Robert Knepper also stars. Lisa Lackey, Tessa Thompson and Rick Worthy guest star.