In Season 4, Episode 21 of , titled "Rate of Exchange," the high-stakes battle for Scylla reaches a fever pitch as Michael Scofield is forced to make an impossible choice between saving his brother, Lincoln, or the woman he loves, Sara Tancredi. Key Plot Developments
C-Note and Sucre reunite in Chicago. C-Note reveals he is working with a mysterious benefactor (later revealed to be Paul Kellerman) who claims he can help the brothers gain total immunity if they can provide Scylla. Watch Prison Break S04E21 1
After being captured and tortured by federal agents for information on the brothers, Don Self is left in a vegetative state after the General’s men inject him with a debilitating chemical to keep him quiet. Where to Watch In Season 4, Episode 21 of , titled