Michael creates a lockdown by sabotaging the air conditioning in order to execute his breakout plan properly, and unintentionally causes a riot that gets Sara into huge trouble. Meanwhile, an ex-con is blackmailed into seeing to that Lincoln is killed.

While the riot intensifies, Abruzzi and Sucre join forces. Michael must decide whether or not to save the life of Dr. Tancredi.

Michael sees proof his plan is working, so he begins to overcome the last obstacle. As the escape draws near, the group tries to reduce its number by one and targets T-Bag.

Lincoln is worried about Michael's sanity while Michael has trouble remembering some parts of the prison schematics. Sucre has to conceal the hole in the guard's break room. Warden Pope transfers Michael to solitary after he declines his request.

In an effort to recreate the missing piece of the tattoo, Michael gets transferred to the psych ward, seeking the help of Haywire. T-Bag and C-Note have to join forces.

Michael and Lincoln are eager to locate the Double K ranch where Westmoreland hid his millions. Sucre goes to Las Vegas to prevent Maricruz from marrying his cousin Hector. C-Note gets on a train. Mahone is given an important package.

As Michael reunites with Sara, Mahone and Kellerman strive to make sure they stay apart.On the road with LJ, Lincoln meets his father. Sucre tries to contact Maricruz. T-Bag has a reunion of his own.

With Mahone on their trail, Michael, Lincoln, their father, and Sucre make a run for the getaway plane. Michael's reunion with his father sheds light on his difficult childhood.The women in Bellick and Kellerman's lives coerce their men to confess their sins.A medical emergency forces C-Note to risk it all.

In Mexico, Sucre gets a car but gets in trouble by the police. Bellick has more trouble as the new inmate as prisoners who suffered with him want revenge.

Michael and Sara request Henry Pope's help to retrieve the information that will topple The Company.Mahone pins down an escapee. Sucre discovers a new threat while hitchhiking to reunite with Maricruz. T-Bag brings the Hollander family to his home.

An unlikely alliance forms between Bellick and Sucre while Michael is determined to face the president. T-Bag gets into some trouble when he loses his luggage and C-Note faces major consequences after some of his actions.

A new inmate named Tyge is brought to Sona. After he seemingly recognizes Whistler, Michael's doubts arise. T-Bag enters a new area of commerce.Lincoln goes to the seaside with Sofia. Sucre takes over the side-business of his predecessor.

The Panamanian Army arranges Michael to get a taste of solitary. T-Bag reserves a spot in the escape. Bellick's life turns into an uphill battle. Susan traps Sucre.

Michael, Lincoln and Sucre must crash a police benefit to obtain the next card key. Reeling from another death, Sarah falls back into an old habit. T-Bag arouses suspicion and runs into some old “friends” his first day on the job.

Sara is left with no choice but to take Michael to the hospital as his condtion rapidly worsens. Sucre and Lincoln are faced with unknown territory as they are left in charge of the operation. Elsewhere, agent Self makes a surprising ally.

Michael's reunion with Christina is soured when she drops a bombshell regarding Lincoln, and T-Bag grows determined to prove he is worthy of being a member of the Company.