03/31 - After "helping" Suresh search for more people with special abilities, Sylar's rampage continues with two "heroes" being confronted by the stronger-powered serial killer. Nathan must factor what he's learned from Linderman (guest star Malcolm McDowell) into difficult decisions that will shape the future -- for him, his family, New York City and the world. As Thompson (guest star Eric Roberts) uses every tool at his disposal to find Claire, Linderman drafts Jessica into his far-reaching plans. Meanwhile, Hiro's resolve to "save the world" strengthens in the face of a grim reality. Santiago Cabrera, Noah Gray-Cabey, Jack Coleman, Greg Grunberg, and Milo Ventimiglia also star. James Kyson Lee, Missy Peregrym and Cristine Rose also guest star. Source: NBC
03/30 - Greg Grunberg reveals: In the next episode airing April 23, with the help of Mr. Bennet/HRG, we're all going to break out. It's a really exciting episode and it sets us on this mission to stop Sylar and find the tracking system, because without the tracking system they can't get to Claire, and they can't get to me. The key to the whole thing is getting that computer and wiping it out.
from spoilerfix.com