 Though he travels back and forth several times, William finds his body has become unstable and remains in the parallel world, still communicating with Nina whom he left in charge of Massive Dynamic.During the first season, Walter discovers that William wrote the ZFT manifesto, which is the base for the ZFT members' actions (to prepare for war against the parallel world, by doing experiments of all sorts of weapons - chemical, biological, or even human).In his first screen appearance, William brings Olivia across in the season 1 finale to warn her about the oncoming storm between universes and the identity of the shapeshifter Newton.