The second half of a two-episode storyline, the episode features the aftermath of a Federal Bureau of Investigation (FBI) Special Agent's abduction, which results in the search for not only the agent and her kidnapper but also for the true motive of the spree killings in the previous episode.
Series writer Ken Sanzel used the trawler problem, a real-life application used to find traveling boats, as inspiration for the mathematics included in the episode.
FBI Special Agents Don Eppes (Rob Morrow), David Sinclair (Alimi Ballard), and Colby Granger (Dylan Bruno), along with Dr. Charlie Eppes (David Krumholtz), Don's younger brother and an FBI math consultant, arrive at the scene of an abandoned stolen van at an all-night café and notice that fellow FBI Special Agent Megan Reeves (Diane Farr) is late.
Don receives a call from Crystal Hoyle (Kim Dickens) that she wants her husband, Buck Winters (David Gallagher), released in exchange for Megan, who has been kidnapped.
Meanwhile, the team questions Crystal's ex-boyfriend Billy Rivers (Mark Rosenthal) and his attorney.
The team learns that Brenner arranged a black market adoption for Crystal's daughter through Rivers' attorney.
Charlie then suggests that Don can use the café, the garage, and the place where Crystal dumped Megan's cell phone as starting points for a search.
The team finds Megan, whom Crystal leaves bleeding in an empty hotel room, and rushes her to the hospital, where they, Charlie, and Larry visit her.
At Charlie's house, Don tells his father, Alan Eppes (Judd Hirsch), what he did and asks whether it was possible to start doing the right thing again.
Originally, series writer Ken Sanzel wrote "Spree" and "Two Daughters" as one episode.
During a production meeting, executive producer Barry Schindel made the suggestion for Don to shoot Crystal instead of Ian.
The trawler problem is a real-life application of pursuit curves used to find slow-travelling boats.
Marking his fourth appearance on the series, Lou Diamond Phillips reprised his role as FBI Special Agent Ian Edgerton.
[1] Farr told series executive producer Barry Schindel[3] and several people on set, including Sanzel, about the pregnancy.
[1] Due to the level of violence in the episode, the producers attempted to balance the audience's sensitivities with reality.
Calling both "Spree" and "Two Daughters" "stand-alone", Cynthia Boris of DVD Verdict seemed to enjoy the episode.