S1

S2
The volume begins as a seemingly ordinary group of people gradually become 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. Volume two 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.

S3

S4
Volume Three began with the assassination attempt on Nathan Petrelli, and the consequences it has in the future. In addition, several villains escape from the confines of Level 5, and the Company attempts to recapture them. Arthur Petrelli heals from systemic nerve damage with the help of Adam Monroe's healing abilities and eventually gains a few of the villains while later luring in Mohinder Suresh, Nathan Petrelli , Tracy Strauss, Elle Bishop, and Sylar. Their objective is to create a formula to give people abilities but after many failures they soon realize they need to find the "catalyst", which is contained within a person. On May 4, 2009, NBC confirmed renewal of Heroes for a fourth season consisting of 18 to 20 episodes. The season is set to start with a 2 hour premiere on Monday, September 21, 2009. Madeline Zima will join the cast as Gretchen, Claire's quirky roommate. Rick Worthy will have a recurring role, playing Matt's new partner, an experienced and capable Los Angeles cop. Robert Knepper joins the cast as Samuel, a new villain. Ray Park has reportedly also been cast "for a sizeable arc".