Hiro's 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, Samuel's plan to impress his long-lost love, Vanessa, takes a terrifying turn.

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.