【Season 4, Episode 1: Scylla】
In Los Angeles, Michael is tracking Whistler and Gretchen seeking revenge for the death of Sara. They go to the Roosevelt Hotel to buy a fifty million dollars card called Scylla. Whistler kills the sellers, copies the card but he is surprised by Michael.
Season 4, Episode 2: Breaking and Entering
In LA, General Krantz tells Wyatt that he wants Michael, Lincoln and Mahone dead. Agent Self forces Michael and his crew to wear monitor around their ankles, and their first assignment is to find the Scylla card. Mahone recalls that Whistler delivered the card to a card holder, and he noted that the driver probably would be a retired military.
Season 4, Episode 3: Shut Down
In Los Angeles, Michael argues with Agent Self since there are six cards and not only one. The agent gives the rest of the day to find a second card holder; otherwise the project would be shutdown by The Powers .
Season 4, Episode 4: Eagles and Angels
The boys now know who the five other Scylla-holders are, and trace one to Turkish consul Tabak's wife Lisa, who is about the leave on mission for the General but first attends a fallen LAPD men benefit, 'Eagles and Angels'.
Season 4, Episode 5: Safe and Sound
Sara notes that Bruce's credit card is missing from her purse and she sees Wyatt on her tail; she runs and succeeds in escaping from the hit-man.
Season 4, Episode 6: Blow Out
Michael and his group are in the jockey chasing card number five. Michael and Mahone plant the device in the office of the operation manager; Bellick argues with the clerk in the counter and Lincoln plants a device in the horse's gate,.
Season 4, Episode 7: Five the Hard Way
Gretchen tortures T-Bag and asks about the Bird's Guide and Scylla. Meanwhile, the Agrishow executive Howard Scuderi travels with his wife and the fifth card to Las Vegas.
Season 4, Episode 8: The Price
Lincoln proposes to crash the General's car to copy the last card using the trick he did in 2001, in Chicago, to rob a wallet. Michael tells Sara that Gretchen is alive and dealing with Agent Self a partnership together with T-Bag.
Season 4, Episode 9: Greatness Achieved
Lincoln unsuccessfully beats up Wyatt, trying to force him to call General Krantz and tell him that he killed the brother.
Season 4, Episode 10: The Legend
Michael's group is sad with the death of Bellick, and they demand that Self sends his body to his mother. Michael asks for the missing pages from Self and Gretchen returns and tells that The Company is moving Scylla to a bunker in Pennsylvania. Michael tells that the map does not make sense, but he deciphers the message "CME David Baker" meaning "See me David Baker".
Season 4, Episode 11: Quiet Riot
The team is finally ready to break into the Company's Scylla facility. After his diagnosis, Michael considers taking Sara's advice to have his urgent surgery immediately, but still presides over the job.
Season 4, Episode 12: Selfless
Despite his headaches, Schofield successfully breaks in. The General rushes a security team down, and thus provides the last missing element: his sixth card! He's still confident to bribe the team or just keep them locked in.
Season 4, Episode 13: Deal or No Deal
Self calls Herb and says that Lincoln has killed Miriam and pretends that he was also shot by Lincoln. The disturbed General Krantz recalls Michael's words; during a meeting with the board of The Company, he is questioned by Howard Scuderi and he unexpectedly kills him and asks if there were any further questions from the other participants. Lisa is shocked with the attitude of her father. Herb calls Michael believing that Lincoln has killed two federal agents.
Season 4, Episode 14: Just Business
Sara gives Michael another injection tells him he needs a doctor. The lookout Lincoln keeps watching on the outside of the warehouse; when Self throws gas bombs trying to force Michael and his group to leave the place, Lincoln surprises Self, hits him on his back and brings him into the warehouse. Self justifies that his motivation was not personal, just business, and proposes to sell Scylla and share the amount among the whole group; however Gretchen appears out of the blue and balances the situation and they leave the warehouse without a shootout.
Season 4, Episode 15: Going Under
General Krantz tells Lincoln that the price of Michael's surgery is the safe return of Scylla. Lincoln tortures T-Bag to find the location where Self and Gretchen will deal with the buyer; after losing two teeth, T-Bag says that the meeting place will be at Arlington Pier at 3:00 PM. Lincoln and Sucre head off to the Pier, but Rita calls Gretchen and says that the Company abducted T-Bag.
Season 4, Episode 16: The Sunshine State
Lincoln calls Sara from Miami asking for news about Michael and tells that he is trying to retrieve the Scylla for The Company with Gretchen, T-Bag and Self. They find a lead in the Grafton Club, and Lincoln goes to the place where he abducts Tia Hayden trying to find the representative of the owner of Scylla. Meanwhile Michael awakes locked in a house in the woods under the surveillance of bodyguards of The Company.
Season 4, Episode 17: The Mother Lode
Lincoln and his men (Self, T-Bag, Mahone) are trying to find Scylla. They try to find a clue for the key from the fake buyer who killed Gretchen. They find a Church and an Estate that matches with key.
Season 4, Episode 18: VS.
Realizing Linc isn't going to stay out for days as she asked 'to give the Company a maternal head', Christina orders her own son sniper-shot, but the team saves him.
Season 4, Episode 19: S.O.B.
Michael warns Linc that scientist Vincent Sandinsky is somehow in league with their mother Christina. The general takes torturous charge, and traitor Vincent.
Season 4, Episode 20: Cowboys and Indians
Michael and Lincoln are trapped in the Panda Bay Hotel and seek a means of escape. Self tries to help them while General Krantz sends a man to capture the brothers.
Season 4, Episode 21: Rates of Exchange
Krantz holds Sara captive, Christina even shot Linc in a lung for urgency, each demands Scylla as ransom. Michael tries to cheat his mother, but only a driver is hurt in his tripwire explosion.
Season 4, Episode 22: Killing Your Number
According to Michael's plan, Malone hands a fake Scylla to Christina. It's booby-trapped but ends up in the hands of FBI Agent, Chris Franco. Bagwell meets Sucre and C-note, but is caught while they hope that an offer of help is real.
Season 4, Episode 23: The Old Ball and Chain
Original Air Date—24 May 2009
参考资料：IMPd