The third season of Numbers, an American television series, premiered on September 22, 2006 with the episode "Spree" and had its season finale "The Janus List" on May 18, 2007. Charlie and Amita intensify their relationship, as do Larry and Megan. Amita has troubles adjusting in her new role as a CalSci professor, and Larry announces his leave of absence—he will be on the space station for six months, which greatly distresses Charlie. Dr. Mildred Finch, the newly appointed Chair of the CalSci Physics, Mathematics, and Astronomy Division, initially troubles Charlie and his colleagues, as Alan dates her. Don dates Agent Liz Warner, questions his ethics and self-worth, and receives counseling. Charlie sees Don's therapist and the two understand one another more. Alan engages in some FBI consulting with his knowledge of engineering, and Larry returns from the space station, although disillusioned. The finale wraps up with a revelation that shakes the whole team.
Don is on the trail of a criminal couple consisting of a 30-year-old teacher Crystal Hoyle (Kim Dickens) and her 17-year-student Buck Winters (David Gallagher) who are committing crimes across the country. Charlie and Amita's relationship changes and Alan decides to move out. The episode ends in a cliffhanger with Hoyle (Kim Dickens), the 30-year-old teacher, taking Megan hostage. Lou Diamond Phillips appears again as Agent Ian Edgerton.
The first of a two-episode story, followed by Two Daughters.
The team jumps into action after learning that Crystal Hoyle (Kim Dickens) has taken Megan hostage and work against the clock and ever-decreasing odds to save Megan before it's too late. Sequel to Spree.
The death of a Chinese interpreter outside a nightclub who was knocked down and fatally injured by a car at first appears to be an accident but Charlie's theory later suggests that it was murder and the resulting investigation leads Don and his team to investigate a possible mole from within the Department of Justice. Colby covers up information on Don's case for a friend (Shawn Hatosy) and is left stunned when he finds evidence suggesting that his old friend is the mole that Don and the team are looking for. Charlie is upset when Larry publishes a paper without his help.
The team investigates the death of a man armed with a sophisticated statistical analysis that can identify the winning horse at a race track. Philip Casnoff guest stars.
First appearance of:Aya Sumika in the recurring role of FBI Agent Liz Warner.
A minor league baseball player trying to get back to the majors is found dead of steroid abuse, leading the investigators to an unusual chain of suspects. Jay Baruchel portrays Oswald Kittner. Bill Nye makes his second appearance in the recurring role of Charlie's CalSci colleague engineering professor Bill Waldie. Jon Hamm also guest stars.
Mysterious cancer clusters are found around a number of elementary schools whose playgrounds were all paved by the same company. A new CalSci administrator (Kathy Najimy in her first appearance as recurring character Dr. Mildred Finch) annoys Charlie and his colleagues, while Alan dates her. Joshua Malina, Bob Gunton, Deidre Lovejoy, and Erica Gimpel also guest star.
A California State Senator and a psychiatrist are murdered; neither have much in common with the other except for one thing...they both turn up dead on Don's watch. While the circumstances of their deaths are different, Don thinks the two murders are related, and tries to prove his hunch right. What he finds may bring to light a deep secret the government has been hiding for years. Tom Amandes guest stars.
Don and Charlie track a killer who has murdered several sex predators. The predators took advantage of teenage girls they met in chat rooms. Meanwhile, Larry is ready to begin an adventure with NASA. Guest stars include Robin Weigert, and astronaut Buzz Aldrin as himself in a non-speaking cameo appearance.
Don, Charlie, and the team search for a polygamist who is on the FBI's Ten Most Wanted List for rape and murder. Guest stars include Teri Polo, Joshua Malina and Anne Dudek.
After an extremely expensive yacht sinks in the middle of a race, Charlie finds himself caught between a rock and a hard place when both Don and the NSA need his help on the case. David Clennon, Jason Beghe, and Titus Welliver guest star.
When two police officers are killed while eating dinner out, Charlie tries to figure out where the killers will strike next while Don's superiors make him see the department shrink (Wendell Pierce) to help him deal with the aftermath of the Crystal Hoyle Case. José Zúñiga guest stars.
Don and the team reopen a cold case when a bunch of kids playing in an abandoned empty construction site discover a police badge. When Charlie joins the investigation, they attempt to track down the owner of the badge, a police officer who has been missing for seventeen years but when the team discover that the dead cop was on his way to Internal Affairs, the investigation takes a turn. Meanwhile, Alan is informed that he's being sued. Lance Reddick and Hassan Johnson guest star; Will Patton makes another appearance as LAPD officer Lt. Gary Walker.
One of David's closest friends is called into question after a man dies during a mixed martial arts sparring match. When it turns out that this is not the first time such an event has happened, things look even worse. Charlie is busy practicing what little he knows about poker, so he can take Larry's spot in a tournament. Steven Culp, Lauren Vélez, Bruce McGill and Arye Gross guest star.
Don talks to his departmental therapist (Wendell Pierce) again, and while he's gone, the team races against time to find an eleven-year-old boy being held hostage on a $3 million ransom. Vincent Laresca and Michael DeLorenzo also guest star.
Several area murders seem to be tied to voter fraud. Don, Charlie, and the team must find the killers before they strike again. Jay Baruchel and Joshua Malina again appear in recurring roles; William Sadler and Kelli O'Hara also guest star.
When a jet crashes in the middle of a forest, Charlie suspects that there is more to the crash than meets the eye. Lou Diamond Phillips appears again as FBI tracker Agent Ian Edgerton; D.W. Moffett also guest stars.
Don and Charlie hunt for a serial letter bomber and disagree over whether a key suspect, a physics professor working as a consultant on explosives for the Department of Defense who eluded conviction once before, is responsible for the latest murder.
When a former mob hit man on death row suddenly has a change of heart and agrees to confess to his crimes, Don has an uneasy feeling about the whole affair while Larry (Peter MacNicol) returns from his NASA mission. Jeremy Sisto, Wood Harris and Bruce MacVittie guest star. Kathy Najimy makes her final appearance of the season as Dr. Millie Finch.
Don, Charlie and the team take on an unknown group of terrorists who may be using nerve gas to undermine the city's water supply. James McDaniel and Erik Palladino guest star.
A truck loaded with medical relief supplies and $50 million cash is stolen, and someone other than the FBI wants to recover the hijacked shipment. Don and the team find themselves being pitted against blackmarketeers in a race for the supplies and cash. William Russ, Wendell Pierce, LisaGay Hamilton, and William Shockley guest star.
In the wake of a deadly standoff with a mysterious, yet brilliant bomber, Don and Charlie discover that he was poisoned to keep him from exposing a secret while the team are left reeling and stunned after learning that one of their own is a traitor, a revelation that threatens to change the team forever... Martin Jarvis, Shawn Hatosy, and James Frain guest star.
