The major storyline for the fourth season concerns a team recruited by Homeland Security agent Don Self (Michael Rapaport) to obtain Scylla. Although the team initially believes it to be the Company's "black book", it is later revealed to contain information on an advanced renewable power cell. Over the course of the first half of the season, the team obtains cards to access Scylla and break into Company headquarters to steal it. In the first half, main characters are discovered to be alive, others are killed, and Self is revealed to be a double agent and is planning to sell Scylla to the highest bidder. Reluctantly, Lincoln decides to join the Company to get it back, while Michael suffers from a hypothalamic hamartoma. He is treated and operated on by the Company. He later learns that his mother, Christina is still alive and was an agent of the Company, who is revealed to acquire Scylla to sell to the highest bidder. The objective becomes for Scylla to be recovered by Michael and the team and for the General and the Company to be taken down. Eventually, the series ends, but is also followed by Prison Break: The Final Break.
