The first season, known as "Genesis", begins as a seemingly ordinary group of people gradually becomes aware that they have special abilities. Events illustrate their reactions to these powers, and how the discovery affects their personal and professional lives. At the same time, several ordinary individuals are investigating the origins and extent of these abilities. Mohinder continues his late father's research into the biological source of the change, while Noah represents a secret organization known only as "The Company". While coping with these new abilities, each of the characters is drawn, willingly or unwillingly, into the Company's conspiracy to control superpowered people and into a race to stop an explosion from destroying New York City.
Season two, known as "Generations" begins four months after the events of Kirby Plaza. The main plot arc of Generations deals with the Company and its research on the Shanti virus. This research is explored through the Company's founders, whose identities are revealed, as well as through the effects of various strains of the virus. The heroes ultimately come together in an attempt to stop the release of a deadly strain of the virus and avert a global pandemic.
Season four comprised volume five, "Redemption" and takes place six weeks after the events of season three. The heroes try to return to their normal lives, Peter returns to his job as a paramedic, while Claire attends college. Sylar's acquired abilities begin to manifest as Nathan struggles to maintain his identity and Sylar's consciousness, trapped in Matt Parkman's mind, taunts him and seeks out his body. A carnival group is introduced, led by Samuel, who tries to recruit more people with abilities into his carnival family in hopes of creating a community for these people where they are welcome to be open with their abilities and respected by outsiders. The end of the Season 4 finale begins Volume Six, "Brave New World", in which Claire reveals the existence of people with special abilities to a group of reporters and photographers.