After getting up-to-date on Beth Ann's kidnapping, Olsen orders Dunn and Finley to take Gibson into custody before he does something radical to get his daughter back. Meanwhile, Beth Ann's kidnapper allows her to remove her blindfold - she sits in what looks like a long-abandoned child's bedroom. It's not long before she discovers what appears to be a page out of Gibson's notebook.
Gibson flashes back to the kidnapper's call to issue a demand that he confess his crime at the Ballard school on Sunday - or Beth Ann will die. Gibson marches downstairs to his basement murmuring to himself - he will not confess. He grabs a sledgehammer, breaks open the floor and pulls out a trunk packed with computers, passports, weapons and more. Gibson's up to something.
Dunn and Finley arrive at Ballard just as POTUS and FLOTUS walk onto the stage for Beth Ann's vigil, and Gibson declares his refusal to give into Beth Ann's kidnappers. Sensing danger, Dunn and Finley escort POTUS and FLOTUS from the building. In the car on the way home, FLOTUS' nose starts bleeding; she collapses and is rushed to the hospital. It's not long before Dunn and Finley are interrogating Gibson about FLOTUS, prompting him to flash back. He stands in his basement applying serum onto his finger. At the vigil, he shakes FLOTUS' hand, rubbing onto her skin the serum that caused her stroke. Finley and Dunn proceed to the hospital to question Kyle, who says Gibson asked him to make sure his parents attended Beth Ann's vigil. Kyle starts to understand... Gibson's the bad guy. At that very moment, an unattended computer in Gibson's basement sends a text message to Amber.
Still in custody, Gibson meticulously washes his hands while Olsen reviews the videotape of the vigil and notices Gibson shaking FLOTUS' hand. Olsen immediately bursts into the interrogation room and demands to swab Gibson's hands. Back at the hospital, POTUS informs Kyle that FLOTUS has passed away. Finley receives a call from Olsen that Amber's missing. The FBI learns Amber withdrew $500 from an ATM. The bank's security camera footage reveals no one kidnapped Amber; she's driving around with Ian.
Amber and Ian have both received anonymous text messages with instructions to save Beth Ann. After exchanging the $500 for a container of diamonds, they drive to an army surplus store to hand over the diamonds and ask the man behind the counter for the third dressing room. As Amber walks around the store she spots a pile of masks identical to those worn by the kidnappers. Unhinged, Amber dons a mask, grabs a gun, and with Ian's help, holds the storeowner on the ground demanding he turn over Beth Ann. Luckily, Dunn and Finley barge into the store to persuade Amber to drop the gun. Amber and Ian explain everything to Dunn and Finley. Dunn tries to contact Meg, but she does not answer. Finley shows Dunn a text on Amber's phone meant for the man behind the counter, which reads "THE DIAMONDS PAY TO KILL THE BOY AND HOLD THE GIRL." Dunn and Finley ponder the message, thinking about all the aspects of Beth Ann's kidnapping when they realize everything leads back to Meg. Meg has Beth Ann! That's when a light bulb goes off. Dunn knows where her sister has stashed Beth Ann.
Meanwhile, Gibson's two escorts receive a text to move him. In the car, Gibson surreptitiously pulls out one of his teeth and breaks it in half, which emits a noxious gas. He blows the gas to the front of the car while covering his mouth. Once he's escaped, Gibson calls Meg demanding she release Beth Ann. Meg heads to the house where she's keeping Beth Ann, unaware that Gibson is on her tail.
Gibson shoots Meg outside the cabin Dunn and Meg frequented as kids. Inside, he finds Beth Ann reading one of the pages of his notebook. She knows the truth. Gibson tries to tell Beth Ann he's not responsible, but she doesn't buy it. By the time Dunn and Finley get there, Gibson is over the edge and holding Beth Ann at gunpoint. Finley instructs Beth Ann to look into Gibson's eyes, which allows Finley to fire a bullet into Gibson's shoulder. Gibson releases Beth Ann, and Dunn arrests Gibson. Gibson whispers to Dunn, "You're a parent. You understand why I did what I did..." After the dust settles, Dunn and Meg share a moment. Meg came to the cabin knowing Dunn would come looking for her eventually. When Dunn points out Meg will go to jail for kidnapping, she responds, "But you got him. You got Gibson." Finley reads Dunn the final task on Gibson's list, "My family reunites and I go home." Just then, Gibson's computer screen lights up and sends one final text...