Arrow of Time

"Arrow of Time" is the 11th episode of the fifth season of the American television show Numbers. In the episode, Federal Bureau of Investigation (FBI) agents track an escaped prisoner who is seeking revenge against one of their own. Written by series writer/executive producer Ken Sanzel, the episode continued two storylines. The first storyline continued one that began with two episodes shown very early in season three. The other was originally launched in the season four season finale "When Worlds Collide". "Arrow of Time" first aired in the United States on January 9, 2009. Plot summary While Dr. Charlie Eppes (David Krumholtz), a CalSci math professor/FBI math consultant, rehearses a lecture on entropy and his brother, FBI Special Agent Don Eppes (Rob Morrow), is at temple, federal prisoner Buck Winters (David Gallagher) escapes from prison along with two other prisoners. As Winters and his fellow escapees are federal prisoners, the Los Angeles Police Department calls FBI Special Agents David Sinclair (Alimi Ballard) and Nikki Betancourt (Sophina Brown) to the scene of an abandoned car and hands the FBI agents a rope made from dental floss. David explains to Nikki that, two years prior, Buck's wife, Crystal Hoyle, kidnapped fellow FBI Special Agent Megan Reeves (Diane Farr). Don allowed Buck to be tortured in order to learn Megan and Crystal's location. At a briefing at the FBI office, Don acts as though he is not bothered by the news of Buck's escape. Don's girlfriend, Assistant United States Attorney Robin Brooks (Michelle Nolden), becomes worried about Don as the case should be personal to him. FBI Special Agent Liz Warner (Aya Sumika), who knew only about Megan's kidnapping and had learned about Don's actions from FBI Special Agent Colby Granger (Dylan Bruno), confronts Don about his actions. David and Liz take the rope to CalSci to be analyzed by Charlie and Drs. Amita Ramanujan (Navi Rawat) and Larry Fleinhardt (Peter MacNicol), Charlie's friends and fellow FBI consultants. When Charlie and Larry learn of Buck's escape, Charlie is surprised, as Don had not told Charlie about the escape. Larry is visibly upset as Megan was his girlfriend at the time of her kidnapping. Charlie's calculations reveal that the prison break had been planned for months and that someone outside of the prison had to supply the dental floss. Colby and Nikki bring the girlfriend of one of the prisoners in for questioning.