Martha's chief of staff Naomi Van Horn is making supper for her foster daughter Maddie and trying to get her to come to the table. When Maddie refuses, they have a struggle and a nearby glass water pitcher shatters by itself. Her mother realizes that Maddie caused it with her mind. Her mother panics and tries to call the foster home and Maddie goes up to her room as the windows vibrate behind her. As Maddie hides beneath her bed, the aquarium, the windows, and the lamps shatter, raining her foster mother with broken glass. The mother emerges from the wreckage and stares as a mirror vibrates then shatters in her face, killing her.
A deputy drops off Maddie with Martha and Clark after investigating the murder. Martha reveals Maddie hasn't been able to speak since her birth mother died at age 3. Over Clark's objections, Martha wants to call Lionel who ran the foster organization. Clark talks to Maddie who is drawing a tree and manages to get a smile out of her. Lex and Lana come back to her dorm room from a dinner after Lex has revealed his information about Fine and his supposed government connections. Chloe comes in and notices them and makes a hasty exit.
The next morning Clark shows Maddie around the barn and has her turn around so he can superspeed assemble a hay pile to leap on. While she pets Shelby he hears Maddie whispering to the dog and promises not to say mean things to her. She talks to him and they chat, but Lois barges in and Maddie goes silent. When Lois gets a bit insistent Maddie frowns and the light bulbs shatter. She runs out and Clark goes into the house after her and Maddie explains she didn't kill Naomi as her powers don't work through walls. Clark takes off and asks Lois to stay with Maddie.
Clark checks in with Chloe who has Maddie's background and determined that Maddie's birth mother died in a freak car accident when her windshield cracked. Lois is taking Maddie out about the farm, but the girl makes a break for it to find Shelby. Lois manages to calm her down just as they're interrupted by Frank Colbert from Child Services, who tries to take her away. Lois tries to explain without much success.
Lex is checking up on videos of Milton Fine being seen across the world when Chloe arrives to confront him about his taking advantage of Lana. Lex denies any romantic involvement and Chloe warns him not to hurt Lana.
Colbert gets Maddie in the car despite Lois' warnings. When she goes to get Maddie's belongings, the car windows start to vibrate and Maddie sees a man standing just out of sight of Lois. The windows explode, killing Colbert, and a badly injured Lois can only look on as the man takes the car and leaves with Maddie.
Clark meets Lois at the hospital and gets a description of the man. Maddie has slipped away to try and call Clark but the man catches up to her – he's her dad. Maddie accuses him of killing Naomi and his wife and the man admits it. He shows her a crystal butterfly and demonstrates that he can control crystal and glass as well, creating as well as destroying.
Chloe has identified the man as Tyler McKnight, Maddie's birth father who was imprisoned and sentenced to Belle Reve after stealing seven diamonds. He goes to McKnight's mother, who is unaware that he's out or that he has a granddaughter. Clark sees a stained-glass window sketch from the Talon that has the missing diamonds in it. Tyler has taken Maddie to the Talon and recovers the diamonds. He offers them to Maddie but she refuses. Clark comes in and Tyler tries to direct the glass at him, but Clark throws him into a case and then comforts Maddie.
Lana has heard from Lex and confronts Chloe at the Daily Planet. Lana denies any romantic involvement with Lex and tells Chloe to let it go. Clark helps Lois back to her apartment and talks about Maddie going to stay with her grandmother. Martha comes in and announces that Lois will be taking over as her chief staffer, and Lois agrees.
The deputy takes Tyler out of the hospital but McKnight kills him with his own glasses and makes his escape. Maddie is at the Kents helping out and Clark talks about his father. Maddie would rather stay with them but when Clark tries to explain Maddie starts to lose control of her powers. Clark gets her to calm down.
That evening Clark and Maddie come downstairs and find the door window broken. He goes out to the barn to find Martha with a piece of glass floating at her neck. Tyler demands that Clark bring his daughter to her but Clark uses his heat vision on the glass. Tyler throws every piece of glass in the barn at him but it spins around – Maddie has taken control. Clark convinces her not to kill him and she lets the glass drop.
Clark convinces Maddie to go with her grandmother and assures her she can call him if she ever starts to lose control. Maddie goes after leaving Clark with a new more cheerful picture. Chloe is happy that Lois can provide her with information from the capital and Clark asks about Lana. Chloe is angry that Clark is using her as a "spy," but backs off when Clark wonders if there's something she's not telling him. Lex is on the computer tracking Fine when Lana comes in to talk about their relationship, or lack thereof. He impulsively kisses her, apologizes, and she kisses him back before running out of the room.