Cal and Zoe are about to witness the execution of convicted kidnapper and murderer Jason Wilkie, when Wilkie proclaims his innocence, saying that the Pied Piper kidnapped his victim, a boy named Rex. Cal believes Wilkie, tries to get a stay of execution, but fails.
Watching a newscast, Gillian tells Ria and Eli that 17 years ago, this was Cal's first case that led to a murder conviction -- and Zoe was the prosecutor. Meanwhile, Cal asks Zoe for the trial transcripts and gets turned down.
At the office, Ben plays a call for Cal and Gillian that Rex's family received before the kidnapping. During the call a child's voice recites a nursery rhyme, ending with the line, "Ready or not, here I come!" The boy's aunt and uncle, Faye and Charlie Sheridan, received a similar message this morning, and FBI analysts say it's the same voice. Gillian asks if Cal was trying too hard to help Zoe, which Cal denies, but says Jason wasn't lying.
Cal accuses the Sheridans of faking the call, knocking a vintage Home Fed Diner sign off their living room wall; then he apologizes and leaves. And Ria tells Eli the police were unable to trace the source of the original call.
Jason's brother, Kevin, confronts Gillian at the office and threatens to file a wrongful death suit against the Lightman Group. Gillian requests footage of Jason's execution and last week in prison.
Ben, Cal, and Gillian tell the Sheridans that they'll be listening in on any future calls, when the college roommate of their eldest son, Oliver, reports him missing. When Ben informs Cal that Oliver had an audition for a "men of adventure" college calendar, they question the photographer. Cal discovers nude male mags in safe of the photographer, who is nursing a leg wound. The photographer confesses coming on to Oliver, who got violent, then left for parts unknown.
Eli tells Ria about the threatened lawsuit -- Gillian recently reduced the firm's liability to cut costs -- and his plans to join rival Jack Rader's company. Ria remains loyal. Gillian asks for their help. Meanwhile, Zoe asks Gillian to talk to Cal, who refuses to take her calls.
Cal watches vintage tapes of Jason claiming he tells all his secrets to Beth -- his dog. Cal says he's trying to get off on an insanity plea and Beth is actually is his ex-girlfriend. But she checked into a psychiatric hospital, claiming she's suicidal, two days ago. Then the Sheridans receive another phone call from the same child's voice, but this time asking riddles and mentioning Oliver's disappearance. The call is untraceable.
Cal heads for the psych ward, acts crazy, and gets held for observation. Cal cozies up to Beth, determines she's not suicidal, just scared for her life because a friend of Jason's called, said he's watching her, and threatened to kill her. She doesn't know who, only that Jason met him at a children's summer camp -- and called him the Pied Piper. Cal wants out. The doctors won't let him go.
Ben and Gillian inform the Sheridans that they've found Oliver's car and jacket, but he's still missing, when another phone call arrives with more teasing questions and a claim to know where Oliver is.
Cal asks Zoe to file the paperwork that would get him out of the psych ward. She won't do it until Cal tells her how he feels. "Upset, scared, and rattled," says Cal. Zoe gets him released.
Gillian analyzes tapes of the calls, noting Rex and Oliver are eldest sons. Cal explains "the Pied Piper" is a real person's nickname, and wonders if Jason met him at a music camp. Ria and Eli meet with Kevin, and Ria, flirting outrageously, hands him her phone number. Kevin agrees to hold the lawsuit until Cal's investigation is complete.
Meanwhile, Cal gets a phone call from the child's voice with more teasing questions, including asking if he knows where Emily is.
Cal frantically calls Zoe -- who doesn't know Emily's whereabouts -- and Ben, when Emily strolls in. Cal shows Emily vintage photos Jason's mother gave Zoe to prove he was a good boy. There are three brothers in the pictures -- William, the eldest, died of pneumonia as a child -- and Kevin is holding a clarinet.
Cal says Kevin made the calls and kidnapped Rex, but had Jason kill him to avenge the death of their eldest brother. Gillian explains William contracted pneumonia after their father lost his job at the Home Fed Diner, which was torn down by the Sheridan family's company. (The brothers blamed the Sheridans for their family's lack of money to get William treatment for three days.) After Jason was executed, Kevin wanted more revenge -- and Oliver's been gone for three days.
Ben reports that Kevin has disappeared. Cal and Ben go to a building project where Kevin was chief engineer until it was shut down last month. When Cal notices a wall that's out of place, he breaks a hole in it and finds Oliver, alive. But then Kevin attacks him from behind. Cal stabs him with the hand pick, Kevin is captured, and Ben finds the equipment he used to make the calls.
Cal returns to the office, where Gillian notes Jason's last prayer included confessing he killed Rex. Later, as Zoe tends to Cal's bandaged head, Emily asks if they'll buy her a car to make it easier for them to keep track of her. "Dream on," says Cal.