Cal comes home and finds Emily listening to music with her friend Amanda, whose dad, Wayne, has been in a private mental hospital for five years. Amanda's unsure whether they're helping him or just medicating him for the money, and she asks for Cal's help.
Cal goes to the hospital and finds Wayne angry that another patient is stealing others' fruit. Cal tells him to release the anger. Wayne grabs the thief, who pulls a knife, which Wayne takes away. When orderlies and Dr. Grandon arrive, Cal explains what happened. Grandon wants to inject Wayne with a sedative. Wayne holds the knife to his throat. Cal persuades him to drop it, then the orderlies take Wayne away.
Gillian finds Cal at home baiting a rattrap, notes that he's already decided Grandon is hiding something, and wonders why Wayne was institutionalized.
At the Lightman Group office, Eli is showing photos of Wayne threatening to leap from a bridge when he's interrupted by Grandon's arrival. After Cal voices Amanda's suspicions, Gillian asks why Wayne's condition hasn't improved.
When Eli and Ria visit Wayne's sister, Gina, at her thoroughbred stable, she claims that Amanda - who lives with Gina because her mom died in childbirth - is away.
Cal and Gillian go back to the hospital. Grandon says that Wayne won't speak to people he doesn't trust, so Cal covers the security camera and sends Grandon away. Cal notes that Wayne won't drink his juice, so Cal does. As Wayne clutches a stack of letters, Gillian observes that he misses Amanda and Cal offers to help.
Back at the office, Eli and Ria tell Gillian that Wayne's father, wealthy racehorse owner Richmond Dobar was diagnosed as a paranoid schizophrenic, treated privately for two years, then hung himself. Ria adds Gina is lying about Amanda's whereabouts.
Cal and Gillian question Gina, then Amanda about the bridge incident. After helping himself to a tray of muffins, Cal mentions his own mother's insanity. Noticing Amanda's fear, he inspects her journal, finding a drawing of a dark, grinning face. Then Gina gives them letters from Wayne saying that Amanda doesn't write him, adding she wants to be sure Wayne's getting proper help. Gillian finds these letters alternate between incoherent and lucid.
Cal returns to the hospital, finds Wayne eating the muffins that Amanda brings when she visits and tells him that they're leaving. When Grandon and an orderly block them, Cal suspects Wayne's juice contained drugs; he head-butts the orderly and then passes out.
Cal awakens, wearing an inmate's smock, and fantasizes that his mother is in the room. They embrace and she asks if Emily is anything like her. "A little," replies Cal. Grandon shows Gillian the security footage of this, admits sedating Cal after that head-butt, and notes that the law allows Cal to be held for 48 hours. Then he doses Cal again.
Grandon tells Gillian that he didn't give Cal any hallucinogens, but Gillian finds Cal too scattered to hold a meaningful conversation and leaves the room. When Cal asks Wayne about sedatives, Wayne admits to only pretending to swallow his meds. Meanwhile, a worried Emily goes to the office and asks Ria why Cal hasn't returned home.
Later, as Gillian and Cal take a walk around the hospital, Cal trips an alarm that sends Grandon running out of his office, which Cal then enters with Gillian standing watch. Cal gathers up an armload of pills and calls Eli, but Emily grabs the phone. Cal tells her that he's OK and reads the contents of pill bottles to Eli until Grandon and the orderlies drag him away.
Gillian returns to the office and reassures Emily, who notices Gillian's fear. Emily admits her worries are increased because next week is Cal's 46th birthday, which is the same age as his mother was when she died.
Meanwhile, Cal is in his hospital room fantasizing that his father is there. Cal then knocks him to the floor and confronts him about abandoning his family.
Eli visits Cal and says that those drugs were all mood stabilizers that wouldn't cause hallucinations. Cal suddenly remembers eating one of "Wayne's favorite muffins" at Gina's, and after finding Wayne with a tray full of muffins, he hands one to Eli and tells Wayne that he suspects the muffins are dosed.
Back at the office, Ria discovers a half-naked, crazed Eli - and a half-eaten muffin.
When Cal and Gillian accuse Grandon of dosing the muffins, he says that Amanda makes those muffins. Then Eli arrives and confirms the muffins were dosed.
Cal and Gillian summon Gina and Amanda to the Lightman Group office, where Eli shows Gina videotaped footage of him eating that muffin, then hallucinating wildly. Amanda is horrified, but Gina denies everything. Then Cal asks a completely lucid Wayne to step into the room.
As Wayne and Amanda share an embrace, Cal asks Gina why she dosed Wayne. Was it for his half of the estate? Gina replies she did it for the horses, because Wayne never cared about them.
When Cal and Emily return home, she asks if he deliberately got himself admitted. He says, "If I did, I would really be crazy." Then he admits that he saw his mother - and recounts their conversation about Emily - but he says that his father was the real lunatic in the family. Emily happily hands him the birthday cake she baked. Cal doesn't want to hear this, but it's his favorite cake - and the rattrap snaps.A boy named Noah opens a briefcase, finding cash and a notebook written in code. When his mother, Lily, enters, Noah shows her the money - just before her boyfriend, George, arrives.
Meanwhile, Cal hands Emily a gift-wrapped package to give to her mother, who'll she will be visiting in Chicago.