Claire, back home in California, begins attending college, but is having difficulty adjusting when a mysterious death of a student during the orientation puts her back in the spotlight. In Japan, Hiro and Ando continue their quest to help people with abilities and go so much as to advertise themselves. Meanwhile, Angela fears Nathan/Syler will discover his true identity. Matt tries to settle down back in Los Angeles and raise his son and not worry about unexpected visitors. Elsewhere, Peter is using his ability for good when a mysterious carnival clan, led by Samuel Sullivan, arrives in town which could spell trouble for him and everyone else.

Claire and her new friend Gretchen investigate the death 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.

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.

Matt goes to extreme measures to extinguish Sylar , who continues to torment him. Elsewhere, HRG calls in a favor from Tracy to save a troubled young boy whose misfortunes resemble her own. While Claire and Gretchen are being hazed by their new sorority sisters, they realize pledging might not be their biggest problem.

Claire is determined to get to the bottom of the Sorority Rush attacks on her own, until H.R.G. intervenes only to realize he may be the source of her troubles. Meanwhile, Peter's new ability is a perfect fit for his job and gives him the opportunity to help Emma accept her new life. Elsewhere, Sylar's battle at gaining full control over Matt's body escalates with potentially dangerous implications at stake.

H.R.G. hosts an untraditional Thanksgiving dinner. Elsewhere, the Petrelli family gets a surprise guest at their table. Meanwhile, Samuel continues to hold Hiro hostage, as Lydia goes in search for the truth.

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.

Hiros life hangs in the balance as his brain tumor worsens, prompting him to subconsciously deal with some of his past decisions. Meanwhile, Sylar pays Claire an unexpected visit to get answers as to why he isn't quite himself. Elsewhere, Samuels plan to impress his long-lost love, Vanessa, takes a terrifying turn.

H.R.G. enacts his plan to take down the Carnival with the help of Lauren and Suresh. Sylar visits Matt looking to understand his desire to make a human connection, but Matt has a plan of his own. Meanwhile, Peter warns Emma of Samuel's intentions after his grim vision of the future.

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.