The Numbers: Season 2

When the wife of a judge (Alan Rosenberg) is shot dead while arriving into her parking garage, 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: Scatter plot, Bayesian spam filtering, Buffon's needle problem and conditional probability

Hitoshi Sugoroku starts working as a Nanba Prison guard, much to Hajime's surprise. Uno and Rock don't believe that the "kind and cute" Hitoshi is the little brother of the "vicious gorilla" Hajime and try to disprove that they're siblings by testing Hitoshi's abilities as they escape.

The FBI becomes involved in the stalking of a popular singer (Samaire Armstrong) after she is threatened by an intruder in her house and reveals a series of threatening letters she has received through the mail. Charlie receives an anonymous love letter from someone other than Amita. ---- Mathematics used: Trigonometry, curvelet analysis, Forensic Information System for Handwriting (FISH), spherical astronomy and art gallery problem

Jyugo is saved by Tsukumo from an out-of-control Rock. Meanwhile, Hajime deals with Yamato, who's in the same state as Rock. After finding a talisman on the two of them, Hajime and the others recognize the talismans belonging to Building 5. Hajime decides to go investigate the matter, and with much convincing on Uno's part, takes Cell 13 (except Rock) with him. He leaves Building 13 surveillance to Mitsuru Hitokoe. Mitsuru tells Hajime that they contacted Building 5, but nobody has been respondi

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. Charlie cancels his date with Amita only to discover she already made other plans for that night. Guest stars include Elizabeth Peña and Christian Clemenson. ---- Mathematics used: Transposition cipher, game theory and paper planes

A week-long series of counter-terrorism exercises are put to the test by Homeland Security officials (John Heard and Scott Cohen) in Los Angeles, but the first one is violated by someone who releases a potentially lethal gas in the subway system. Alan hosts a wedding for a girl (Christina Chang) from the Eppes brothers' past. ---- Mathematics used: Percolation theory and diffusion

Don investigates a series of home invasions in which the thieves steal only high-end items from wealthy individuals. Meanwhile, an old adversary (Colin Hanks as recurring character Marshall Penfield) challenges Charlie's breakthrough work, The Eppes Convergence. ---- Mathematics used: Group theory, data-mining, Fourier analysis, calendars, Three-dimensional trilateration, Set theory and projectile motion

Uno explains to Honey and Trois that when Nico's medicine wears off he goes out of control. As Nico's alternate persona awakens, he fights Hachiman. In the meantime, Liang and Upa restrain Daisen Rokuriki and destroy his talisman. Qi interrupts the fight and while Nico attacks him, he injects Nico with his medicine, rendering him unconscious. Hachiman feels as though he has won, however, to his, Liang, and Upa's surprise, Qi injects poison into Hachiman's leg. While Hachiman is unconscious, Upa,

Don learns that someone is poisoning non-prescription drugs made by a leading pharmaceutical company after four people nearly die from the tampering. Guest stars include Lou Diamond Phillips in the recurring role of FBI fugitive tracker and sniper Ian Edgerton, as well as Connor Trinneer and Cynthia Preston. ---- Mathematics used: Information theory - information entropy, graph theory - Seven Bridges of Königsberg and soap bubble theory with Steiner tree

Jyugo has been captured by Ruka Gojou, but is saved by surprise attack from Trois. Honey gets frustrated with Jyugo's uselessness and wants to leave him behind. Eventually, Ruka, Daisen Youriki and Daisen Kokoriki catch up to the group and Jyugo is caught by Youriki. While trying to help Jyugo, Uno is restrained by Ruka. Though initially reluctant, Honey decides to help. The two inmates of Building 3 decide to repay their debts to Jyugo and Uno, and deal with Ruka and the Daisens. After managing

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. Guest stars include Loren Dean and science educator and television presenter Bill Nye in his first appearance in the recurring role of Charlie's CalSci colleague engineering professor Bill Waldie. First appearance of: Sophina Brown as Bianca Styles, before she is cast a

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. Guest stars include Will Patton in his first appearance as recurring character LAPD Lt. Gary Walker, Michelle Nolden in her first appearance as recurring character Assistant United States Attorney Robin Brooks, Tamara Taylor and Aldis Hodge. ---- Mathematics used: Poisson distribution and social network analysis