Hiro learns of his father's death and travels back in time to save him only to realize that he must let events unfold as fate intended. He does however recognize his father's killer. Matt Parkman realizes that he has the ability to implant thoughts in other people's minds. He wants to know the identity of the woman in the photo with his father. When Bob and Suresh kidnap Claire Bennet, HRG and West set out to rescue her but get their own bargaining chip beforehand.

In Haiti, Peter and the Haitian try to rescue Nathan who has been captured by the sinister Baron Samdei and his militia army. At Pinehurst, Mohinder finds himself a captive by Arthur who wants his powers back for a grand master plan, in which Mohinder attempts to find Maya to ask for help since she may be powerless too. In Kansas, Matt Parkman learns the true nature of Daphne without her super speed, while Ando and an immature Hiro seek answers to their powerlessness in a comic book store in the late Isaac Mendez's '9th Wonders' series detailing their conflict as it happens. In California, the powerless Claire is taken to the hospital dying from her wounds, while Sylar and Elle turn from hunters to the hunted when the vengeful Mr. Bennet attempts to track them down to kill them.

Having traveled back in time 16 years, the immature Hiro seeks out his late mother to try to get his memories back, while Claire has a run-in with a younger Noah Bennett when he was assigned by the company to look after the infant Claire and how she may have become the catalyst for the secret formula. Back in the present, Nathan returns to Pinehurst where Tracy introduces him to a group of U.S. Marines that Arthur has recruited to be his army of super-solders once Mohinder gets the catalyst for the ability-giving formula correct and which hopes the formula will be able to cure his disease... and begin Mr. Petrelli's quest for world domination. Peter and the Hatian return to New York and are sent by Angela in desperate attempt to break into Pinehurst to kill Arthur Petrelli before he can complete the formula. Meanwhile, Ando, Parkman, and Daphne seek out a bicycle messenger who may have the last '9th Wonders' comic book works to learn more about the future and where Hiro is and what to do to save him. Elsewhere, Sylar goes rogue once again by disposing of Elle, and then decides to go after both the heroes and villains to steal their powers for himself.

Noah, Claire, Angela, and Meredith find themselves trapped at the Primatech by Sylar who locks them in the building and subjects them all to various mind games. Meanwhile, Matt, Daphne, and Ando seek refuge at the Mendez loft where Daphne plans to steal a sample of the power-giving formula to give to Ando who wants to rescue the powerless Hiro still trapped 16 years in the past, who continues to struggle to find his true origins with his younger self. Back in the present, Peter faces off against Nathan, Tracy and the security detail at Pinehurst to stop Mohinder from reproducing the formula, and finds allies in the form of Knox as well as Flint who also want to stop the production of the formula, leading to a fiery showdown for all.