The second season coincided with the WGA writers' strike, meaning only 11 out of the planned 24 episodes were produced. This forced the producers to redesign the season to encompass only the Generations volume out of the three planned. The planned third volume, Exodus, which was originally designed to be a story arc reflecting the effects of the release of strain 138 of the Shanti virus, was canceled. The planned fourth volume, Villains, was changed to the third volume and moved into season three. Scenes from the volume two finale "Powerless", were reshot to reflect the cancellation of the Exodus volume, and to tie up all the loose plot storylines of Generations.