The first episode of the fourth season opens with Michael avenging Sarah’s demise; he thought it was Gretchen who killed her! Whistler eventually captures Michael’s confidence, when he got to know about the plans of Whistler with Mahone of destroying the Company! The Company discovers and takes the life of Whistler! As the chaos brought about by burning down the Sona, T-Bag, Bellick and Sucre escapes.

Michael is recruited by Don Self after he was arrested this is in exchange for his freedom, as he touches down Chicago to find Sara. Don is aiming at bringing down the Company, he is a known as an agent of the Department of Homeland Security! Lincoln was eventually transferred to Chicago, from Panama with Bellick, Sucre and Mahone. There was a deal made by the two countries. Sara eventually escapes from Gretchen, and the Company takes Gretchen as a prisoner, after the foiled plan of securing important bait! Roland known as the hacker arrested for identity theft, was assigned to join Michael and his team.

They decided to get Scylla, known as the “little black book” of the Company, as it will give the key on how to obliterate their existence! Wyatt on the side as the Company’s agent tracks down Lincoln and Michael. The group finds the black book Scylla; unfortunately, Self deceives them and tries to trade the black book, but eventually fails. Just before the break during the mead season, Michael and Lincoln’s mom’s hiatus is revealed, she is alive! Safekeeping Scylla! April 17th is the start of the second part of the season.