Six weeks after Matt and the others wiped Sylar's mind, the Heroes attempt to go on living normal lives. We are introduced to "family" of carnies with abilities. Angela Petrelli and H.R.G. are in the works of restoring The Company while Claire makes new "friends" at school. Tracy is still hunting everyone from Building 26. Meanwhile, Hiro and Ando start a "Heroes for Hire" business.

Claire and her new friend Gretchen investigate the passing of Claire's roommate Annie, while Noah comes to Peter for assistance. Samuel and Edgar recover the compass, Hiro realizes his new destiny, and Matt is tormented with mental images from a dangerous foe.

Peter faces unexpected consequences for his heroic acts and encounters a reluctant new hero. As Claire continues to adjust to college life, she must figure out how to deal with her ability having been revealed. Meanwhile, Samuel moves heaven and earth to recapture the memories of his late brother Joseph. Elsewhere, Matt struggles with his internal demons as Sylar mysteriously resurfaces.

As "Nathan" starts displaying new powers, he has visions of an incident from his past involving a young girl and decides to investigate. Hiro tries to save a co-worker and learns a truth about himself. Tracy tries to regain her old life and job.

Samuel prepares for new additions to his family, while Lydia warns him of the consequences. Claire discovers that her roommate Gretchen may have a hidden agenda. Meanwhile, Peter finds an unexpected way to connect with Emma, who would prefer to stay distant. Elsewhere, a different side of Sylar emerges as he desperately tries to remember the person he used to be.

Under Samuel's guidance, Sylar starts on a path to rediscover his true identity. Hiro helps Emma accept and understand the great possibilities that go along with having an ability. Meanwhile, Peter enlists HRG to help him find a healer who can save Hiro's life.

Matt goes to extreme lengths to get rid of Sylar's mental influence. Noah and Tracy come to Jeremy's aid when the Cainan police hold the boy for the passing of his parents. And Claire and Gretchen go on a sorority scavenger hunt only to discover someone is taking it deadly serious.

When Hiro travels three years into the past, he has a second chance to save Charlie from the hands of Sylar. However, Samuel's presence serves to complicate Hiro's mission even further. Elsewhere, H.R.G.'s past with his Primatech partner is revealed.

Claire tries to determine who is responsible for the attacks on Gretchen and Annie. Sylar maintains his control of Matt, and Peter uses his newly gained ability to help Emma.

As Matt continues his battle to resists Sylar's mental domination, Tracy struggles to control her ability and Samuel learns how to tap into the full power of his.

As Noah hosts a thanksgiving dinner, an unexpected guest visits the Petrellis. Meanwhile, Lydia tries to discover the truth about one of the carnival's secrets.

Unexpected visitors greet H.R.G.; Samuel's plan starts to come to fruition; struggling to accept the truth, Peter takes extreme measures to get what he wants; Claire's journey leads her to an unexpected destination.

As Claire becomes immersed in the world of the carnival, she becomes increasingly suspicious of Samuel's motives; Hiro goes on a mission to rescue one of his own; H.R.G. recruits Matt to help him take down Samuel.

Claire joins the carnival but begins to suspect Samuel has a secret agenda. Bennet recruits Matt in his battle against Samuel, while Hiro goes to help a friend.

H.R.G. recruits Matt to help him take down Samuel, as they use his long-lost love, Vanessa, to lure him to them, but Samuel has his own plans for Vanessa in the works. Meanwhile, Hiro and Ando go to extreme lengths to save Dr. Suresh. Elsewhere, Peter's introduction of Emma to his mother brings forth visions of a very grim future.

Hiro subconsciously deals with some of his past decisions as his brain tumor worsens; Claire receives an unexpected visit from Sylar; Samuel's plan to impress Vanessa takes a frightening turn.

H.R.G. enacts his plan to take down the carnival; looking to understand his desire to make a human connection, Sylar visits Matt; Peter warns Emma about Samuel's intentions.

Fueled by his vision of Emma in grave danger, Peter attempts to rescue Sylar from his worst nightmare. At the carnival, Samuel reveals H.R.G.s secret past in order to bring Claire to his side. Meanwhile, Lauren makes a bold move to put a stop to Samuel.

Everyone bands together to try to stop Samuel from taking the lives of thousands; Peter teams with an unexpected ally to save Emma; H.R.G.'s life hangs in the balance; Hiro comes to grips with decisions he has made.