Jack believes George to be a compromised agent and blackmails
him to obtain certain information George otherwise refuses to pass on.
After ineffectively getting Jack to report to CTU, Mason
suggests to NSA aide Eric Rayburn that the President call Bauer himself. Mason is unsure of Jack’s plan, and he begins
to question his state of mind when Jack shoots an FBI witness for no reason.
Mason informs Jack that Kim was gone when the agent went to pick
her up. Yet he doesn’t tell Jack that he sent that same agent to follow up a lead on the terrorists. After Mason sees
a confidential report assessing that the intelligence on the nuclear bomb is about 90% accurate, he packs up and heads out
for Bakersfield. Tony doubts his motives for skipping town, but Mason tells him not to question his authority
As he drives toward Bakersfield, Mason is diverted to a possible crime scene in Panorama City where a vehicle has been linked to a terrorist from the federal
watch list. Mason joins the police officers in raiding the industrial complex, and a gunman opens fire on them. Mason realizes
that the shots have released a powdered substance, and when he sees a radiation symbol he tells the cops that they may be
in a potential hot zone. As the HAZMAT team decontaminates Mason, he calls Tony with the news. Tony informs him about NSA’s
request, and Mason instructs him to contact Ryan Chappelle at the District Office to find out why CTU was singled out. A doctor
gives Mason the news that he was exposed to a lethal dose of enriched plutonium. He may only live one more day.
Mason learns that the physical effects of his radiation poisoning
will be evident in a few hours, but he will eventually lose all mental faculty and lapse into a coma. When Tony tries to get
Mason to come back to work, he resists, telling Tony to handle everything himself. Yet after realizing the impact of the blast
on his co-workers, Mason returns to CTU. His first order is to have the injured Paula be kept on site so that she can help
retrieve encrypted intel on the nuke.
Mason orders that Paula be revived immediately, and when
she does, she helps them access the encrypted data about the nuclear bomb. After Mason commends her for helping to save lives,
Paula dies. Knowing that Jack wants revenge against the woman who killed his wife, Mason keeps Jack away from Nina, and questions
her himself. Nina asks for a full presidential pardon for her assistance, and Mason gets her wish granted. When Mason goes
into the restroom to take his anti-nausea medication, Jack follows him and finds the pill wrapper. Jack threatens to reveal
Mason’s health secret to their superiors unless he allows him to interrogate Nina. Mason gives in to Jack’s demand.
Although Jack has given assurances that he won’t let his
anger toward Nina get in the way of his job, Mason pulls him out of the interrogation room when he attacks Nina. Yet when
Jack convinces him that this is all part of his plan to break Nina, Mason lets him finish the questioning. Jack gets Nina
to reveal her connection to Visalia, and Mason orders backup there for their arrival. However, he
sends another agent to accompany them for fear of what Jack might do. When Mason has a fit of coughing, Jack tells him to
go be with his family in his dying hours. Mason brushes off the suggestion.
Mason orders Tony to bring in Reza and Bob Warner at any
cost. A radiation rash appears on Mason’s chest, and he becomes frightened. He calls his estranged son, John, to come
to CTU. When John refuses, Mason has local police pick him up and bring him in. He gives John access to his bank account and
tells him that he is dying. John, who was angry, is now puzzled. Mason asks him to leave town without telling him why. He
hugs his son one last time before sending him away.
After Tony informs him that Bob Warner is a consultant with
the CIA, Mason assails Reza because he believes he is hiding something. Reza, however, continues to claim innocence. Mason
assures Jack that he will send someone to pick up Kimberly. He then gives into Nina’s demands to be delivered safely
out of the country so that she will give up the location of the nuclear bomb.
After receiving the coordinates of the crash landing site
from Jack, Mason discharges a Search and Rescue team there. Michelle pulls up satellite images to show that a ground missile
actually shot down the plane. While looking at her findings, Mason’s nose begins to bleed and he excuses himself. Tony
confronts Mason about his recent behavior, and Mason is forced to tell him the truth about his radiation poisoning. Mason
presses Reza and Bob Warner to admit their involvement with the terrorist after disclosing to them that there is an errant
nuclear bomb in the city. This compels Reza to give up Bob. When Nina takes Jack hostage, Mason and his team listen in to
her request for a premeditated Presidential pardon for killing Jack. When Palmer asks if there is another way to take Nina,
Mason concludes that they have no other choice but to give in to her demands.
As the hours of his life tick away, Mason admits to Michelle
that he regrets working for the government. The Department of Defense had offered him more money than teaching, and he lived
his life miserably with that decision. Mason advises Michelle to find something that brings her joy and to pursue it.
Mason gives Jack the news that Kim was involved in a police
car accident as she was being transported. However, she disappeared into the forest and has not been found. Jack begs Mason
to find his daughter.
Mason gives Bob Warner confirmation that Marie killed Reza,
and Bob discloses a time when she might have been converted to the terrorists’ cause. When Mason discovers that Tony
has been working on finding Kim Bauer, he is angry with him for taking resources away from the terrorist threat. Mason then
orders all the CTU staff to stay focused on their one mission. After Jack learns that the bomb is at Norton Airfield, Mason
orders a full-scale ambush on the site.
The ever-weakening Mason gets word from the NSA that the
bomb is confirmed to be at Norton Airfield, and he orders all teams be sent there. He then gives Jack the news that the Coral
Snake team is acting as a rogue unit to secure the bomb and that they will treat Jack as a hostile enemy if he tries to step
in. When Jack questions this, Mason says that perhaps it’s only political. The Coral Snake team wants to take credit
for stopping the nuke. Mason learns that Division wants to close down his office and immediately take over the investigation.
When a Division head comes to inspect the site, Mason assures him that they are in full control of the situation. Moving their
operation will only deter the search for the bomb. The agent from Division inquires about Mason’s obviously deteriorating
health, but Mason shrugs this off. He continues to hide his increasing pain from everyone.
Mason’s hair begins to fall out and he grows weaker.
While on the phone with Jack, he starts to black out. Jack implores him to give up his post to someone more capable, but Mason
says that he is fine. Mason assures him that he will track the delivery of the decoy bomb and find the identity of the seventh
commando who went missing. After meeting the new systems operator brought in to replace Paula Schaeffer, Mason collapses.
He then hands over control of CTU to Tony because he is not healthy enough to continue. Mason asks him to say goodbye to the
staff for him. He leaves without fanfare.
Despite his failing health, Mason arrives unexpectedly at
Norton Airfield in order to see the case to the very end. When it is decided that a pilot will have to surrender his life
to crash the bomb into the desert, Jack volunteers himself. Yet Mason asks that he be the one to fly the plane because he
will soon die anyway. Worried that Mason’s deterioration may jeopardize his flying abilities, Jack does not give him
the mission. Mason, however, sneaks onto the aircraft unseen. Mid-journey, he comes out of hiding and hands Jack a parachute.
Mason asks to take over the plane now that the roughest part of the flight is over. He questions whether Jack does not want
to go on living since his wife was killed. Jack finally relents, and hands the controls over to Mason. He thanks Mason warmly
and says goodbye before jumping out to safety. Mason, working through his illness, heroically flies the bomb to his own death.