Olivia uncovers a dangerous force that may be connected to past experiments with Cortexiphan. The investigation forces Walter to leave the lab for the first time in years and travel to Massive Dynamic to examine old case files. Walter struggles with his emotional state as he confronts the demons of his past.
Elenco: Anna Torv , Jasika Nicole , Joshua Jackson , John Noble , Mark Valley , Blair Brown , Georgina Haig , Kirk Acevedo , Lance Reddick , Michael Cerveris , Seth Gabel .