List of Numbers episodes (season 2)

Numbers Season 2
200px DVD cover
Country of origin	United States
No. of episodes	24
Release
Original network	CBS
Original release	September 23, 2005 (2005-09-23) – May 19, 2006 (2006-05-19)

Season two of Numbers, an American television series, premiered on September 23, 2005 and its season finale was on May 19, 2006. Season two sees several changes to Don's FBI team: Terry Lake is reassigned to Washington DC and two new members join Don and David Sinclair: Megan Reeves and Colby Granger. Charlie is challenged on one of his long-standing pieces of mathematical work and also starts work on a new theory, Cognitive Emergence Theory. Larry sells his home and lives a nomadic lifestyle, while he becomes romantically involved with Megan. Amita receives an offer for an assistant professor position at Harvard University, but is plagued by doubt as her relationship with Charlie is challenged and her career is in upheaval. Alan begins work and dating again, though he struggles with the loss of his wife.

Episodes

See also: List of Numbers episodes

No. overall	No. in season	Title	Directed by	Written by	Original air date	Prod. code	U.S. viewers (millions)
14	1	"Judgment Call"	Alex Zakrzewski	Ken Sanzel	September 23, 2005 (2005-09-23)	201	11.18
When a judge's wife is shot dead, Don and his team look into the judge's cases to determine if one of his verdicts led to the murder. First appearance of: Diane Farr as Megan Reeves and Dylan Bruno as Colby Granger Mathematics used: Scatterplot, Bayesian Spam Filtering, Buffon's needle and Conditional Probability
15	2	"Better or Worse"	J. Miller Tobin	Andrew Dettman	September 30, 2005 (2005-09-30)	202	11.83
Don and his team are called in when a woman attempting to rob a jewelry store in Beverly Hills is shot by a security guard. Mathematics used: Von Neumann cellular automata, Farey sequence and pseudo-random numbers
16	3	"Obsession"	John Behring	Robert Port	October 7, 2005 (2005-10-07)	203	11.40
The FBI becomes involved in the stalking of a popular singer after she is threatened by an intruder in her house and reveals a series of threatening letters she has received through the mail. Mathematics used: Trigonometry, curvelet analysis, Forensic Information System for Handwriting (FISH), spherical astronomy and art gallery problem
17	4	"Calculated Risk"	Bill Eagles	J. David Harden	October 14, 2005 (2005-10-14)	204	11.09
Don and Megan are called to the murder scene when the CFO of a powerful energy company—who was about to testify against her fellow executives—is murdered at her home and her son is the only witness. Mathematics used: Conditional probability and compound interest
18	5	"Assassin"	Bobby Roth	Nicolas Falacci & Cheryl Heuton	October 21, 2005 (2005-10-21)	205	11.17
Along with David Sinclair and new FBI Agent Colby Granger, Don discovers a secret code during a raid and enlists Charlie's help to crack it. Mathematics used: Transposition cipher, game theory and paper planes
19	6	"Soft Target"	Andy Wolk	Don McGill	November 4, 2005 (2005-11-04)	206	11.13
A week-long series of counter-terrorism exercises are put to the test by Homeland Security in Los Angeles, but the first one is violated by someone who releases a potentially lethal gas in the subway system. Mathematics used: Percolation theory and diffusion
20	7	"Convergence"	Dennis Smith	Nicolas Falacci & Cheryl Heuton	November 11, 2005 (2005-11-11)	207	12.36
Don investigates a series of home invasions in which the thieves steal only high-end items from wealthy individuals. Meanwhile, an old adversary challenges Charlie's work. Mathematics used: Group theory, data-mining, Fourier analysis, calendars, Three-dimensional trilateration, Set theory and projectile motion
21	8	"In Plain Sight"	John Behring	Julie Hébert	November 18, 2005 (2005-11-18)	208	12.44
Megan feels responsible for an agent's death following an explosion at a house where meth is being illegally produced and that the FBI targeted for a bust but the case takes a new direction after Charlie discovers that the drug kingpin was in the FBI office, looking for help in rescuing his supposedly kidnapped daughter. Mathematics used: Flock behavior, steganography and matrices - error correction code
22	9	"Toxin"	Jefery Levy	Ken Sanzel	November 25, 2005 (2005-11-25)	209	12.67
Don learns that someone is poisoning non-prescription drugs made by a leading pharmaceutical company after four people nearly die from the tampering. Mathematics used: Information theory - information entropy, graph theory - Seven Bridges of Königsberg and soap bubble theory with Steiner tree
23	10	"Bones of Contention"	Jeannot Szwarc	Christos Gage & Ruth Fletcher	December 9, 2005 (2005-12-09)	210	12.53
An archaeologist is killed in a museum, and the object she was studying is taken. Mathematics used: Exponential decay and Voronoi diagram
24	11	"Scorched"	Norberto Barba	Sean Crouch	December 16, 2005 (2005-12-16)	211	11.96
An arsonist believed to be part of an extremist environmental group sets a fire at a car dealership that kills a salesman. The group's name is spray painted at the scene and is the fourth such fire, but the first to claim a life. Mathematics used: Combustion and principal components analysis
25	12	"The OG"	Rod Holcomb	Andrew Dettman	January 6, 2006 (2006-01-06)	212	13.93
When Don and his team are called to the murder scene of a Los Angeles gang member, they learn the victim is a fellow agent who had been working undercover. Mathematics used: Poisson distribution and social network analysis
26	13	"Double Down"	Alex Zakrzewski	Don McGill	January 13, 2006 (2006-01-13)	213	12.98
When the FBI is called to investigate a murder at a Los Angeles card club, it leads the agents to unravel a complicated card counting scheme involving a group of college students whose lives may now be at risk. Mathematics used: Probability involving sampling without replacement, time series analysis and randomization
27	14	"Harvest"	John Behring	J. David Harden	January 27, 2006 (2006-01-27)	214	13.22
A South Asian teenager is found in the blood-spattered basement of an old downtown hotel where she was apparently being tortured. The investigation soon reveals that the girl, along with three other missing women, are victims of a black-market organ-harvesting scheme. Mathematics used: Markov chain, ellipses and genetic variation
28	15	"The Running Man"	Terrence O'Hara	Ken Sanzel	February 3, 2006 (2006-02-03)	215	13.31
A DNA synthesizer with the capability of customizing diseases is stolen from the campus where Charlie teaches, and Don fears the thieves may be terrorists out to start or advance a bio-warfare program. Mathematics used: Benford's law, continued fraction, astronomy, and probability
29	16	"Protest"	Dennis Smith	Nicolas Falacci & Cheryl Heuton	March 3, 2006 (2006-03-03)	216	11.94
A pedestrian is killed when a homemade bomb explodes under a car outside of a downtown Army recruiting center. The investigation reveals that a similar bombing occurred exactly 35 years ago at an ROTC office that killed two people. Things take a turn when Don discovers that his father was a member of an anti-war group believed to have been associated with the bombings. Mathematics used: Graph theory, Ramsey numbers and recursive sequence
30	17	"Mind Games"	Peter Markle	Andrew Dettman	March 10, 2006 (2006-03-10)	217	11.67
When the bodies of three illegal-immigrant women are found on government-owned land in a wilderness area, Don investigates and learns a psychic led the police to the crime scene after allegedly seeing visions of the bodies. Charlie becomes extremely annoyed after learning that Don is using the psychic's help to solve the case, maintaining that true psychics do not exist. Mathematics used: Fokker-Planck equation and Binomial theorem
31	18	"All's Fair"	Rob Morrow	Julie Hébert	March 31, 2006 (2006-03-31)	218	12.09
In an effort to find the murderer of an Iraqi woman, Don enlists the help of the victim's cousin, who lives in Los Angeles. Through her cousin, Don learns information about the woman's disturbing connection to Saddam Hussein, which could lead to her murderer. Meanwhile, Charlie reunites with an ex-girlfriend, a best-seller neuropsychologist. Mathematics used: Density, Sudoku, logistic regression and game theory
32	19	"Dark Matter"	Peter Ellis	Don McGill	April 7, 2006 (2006-04-07)	219	13.69
As Don and his team investigate the motive behind two students's deadly school shooting, Charlie uses the school's radio frequency identification system to track the shooters's movements through the school's hallways. But the team are stunned when Charlie reveals that they're looking for a third shooter, someone with motive. Mathematics used: RFID and optimization problem
33	20	"Guns and Roses"	Stephen Gyllenhaal	Robert Port	April 21, 2006 (2006-04-21)	220	12.09
When an ATF agent is found dead amid questionable circumstances, Don demands to take on the case, which revolves around an elaborate bank heist, after he learns the victim is his ex-girlfriend. Mathematics used: Echolocation and biomathematics (DNA sequence alignment)
34	21	"Rampage"	J. Miller Tobin	Ken Sanzel	April 28, 2006 (2006-04-28)	221	12.32
After an unknown man opens fire in the FBI offices, causing carnage and destruction, Don and his team must investigate his motive and his connection to a dangerous arms dealer who is on trial. Meanwhile, Don soon learns that the bullet that killed the sex offender the team interviewed came from Colby's gun, forcing Colby to be put on desk duty for the time being. Mathematics used: Chaos theory, Brownian Motion, Self-organized criticality, Venn diagram and tesseracts/hypercubes
35	22	"Backscatter"	Bill Eagles	Nicolas Falacci & Cheryl Heuton	May 5, 2006 (2006-05-05)	222	12.01
An FBI investigation into a computer hacking scam, which taps into a bank's system to gain access to customer's identities and financial assets, becomes personal for Don when the Russian mob spearheading it comes after him and threatens the safety of Charlie and Alan. Mathematics used: Explicit and implicit functions, geometric progression and exponential growth. Neil Sloane's Integer Sequence Database was also used.
36	23	"Undercurrents"	J. Miller Tobin	J. David Harden	May 12, 2006 (2006-05-12)	223	12.35
Five young Chinese girls wash up on the shore; while Charlie works out where they came from, it emerges that one of the girls is carrying Avian Flu. Mathematics used: Encoding, vector fields, kinematics, n-dimensional space and strange loop.
37	24	"Hot Shot"	John Behring	Barry Schindel	May 19, 2006 (2006-05-19)	224	12.72
When two women are found dead with an apparent drug overdose, Don suspects a serial killer. Charlie's help on Don's case is hindered by his bizarre dream about his mother. Mathematics used: Directed graph, parabolic equations, probability and trajectory

References

NOTE: Refs Need Archive Backup URLs @ http://archive.org/web/

External links

• Numbers at IMDb
• List of Numbers season 2 episodes at TV.com