A father tucks his young daughter in for the night. After the lights are out, the tree outside the window starts tapping on the window, making spooky shadows. Except that bit looks a lot like a monstrous hand, doesn't it? The hand opens the window and a black-robed figure glides into the room. It hovers over the girl as she screams.
Where the children go
Their dad sent them coordinates to Fitchburg, Wisc., but Sam can't find any reports of anything spooky. Maybe his dad was wrong. When they get to town, Sam notices there's only one child on the playground. It's after school shouldn't the playground be crawling with kids? They ask the mother on the playground, who tells them several kids have recently gotten sick hospital sick. The guys put on their suits and go to the hospital, where they pose as CDC officials. Dean notices a hunched old woman staring at him malevolently she's got an inverted cross on the wall of her room. Doctor Heidecker tells them six kids have fallen ill. They thought it was some sort of pneumonia, but it's not reacting to treatment. It's like their bodies are just wearing out. The disease seems to spread through children in families. Dean asks to interview the kids, but they're all in comas.
The guys check out the latest victim's house and find a strange handprint rotted into the windowsill. Dean's seen that handprint before. Once he sees that and meets Michael, the snarky, mature-beyond-his-years boy who helps his mom run the hotel they're staying at when he's not taking care of his younger brother, Dean has a flashback to 15 years ago, when his dad was hunting and he was in charge of watching Sam. Young Dean was less obedient than current Dean why does Dad always repeat the rules to him? Papa Winchester tells him to lock the doors and windows, shoot at anything scary, and above all, never leave Sam. But after three days with nothing to do, little Dean gets stir-crazy and locks a sleeping Sam in the room while he goes to the hotel's arcade. When he gets back, that black-robed figure is hovering over Sam, sucking the life out of him. Dean tries to shoot it, but he distracts it. Papa Winchester comes in and drives it away, but he's furious at Dean for breaking the rules. They leave town, and the monster lives to kill again.
That black-robed figure is a Shtriga, a witchlike figure who feeds off the life force of humans, preferably young children. During the day, it takes on a human disguise often a feeble old woman. Dean decides they need to check out the scary woman at the hospital, but when they get there, she proves herself to just be a scary, crazy old woman. Oops. When they get back to the hotel, they find out Michael's brother has fallen sick.
While Dean goes to the hospital again, Sam does some research dozens of children tend to die from a mysterious illness every 15 or 20 years in small towns around here. The Shtriga is just getting started. Then Sam sees a picture of Dr. Heidecker tending to the sick kids but it's in a newspaper from 1893.
To kill the Shtriga, the guys need to shoot it with consecrated iron while it feeds. For that, they'll need Michael's help as bait. He initially refuses, but eventually agrees after all, he'd do anything for his little brother. The guys wait for the Shtriga to attack it has to be seriously involved in feeding or it will get away. It finally attacks, and the guys burst in. They shoot it, but it's only mostly dead it attacks Sam and starts to suck the life out of him. Dean shoots it while it's feeding, and the Shtriga is finally dead.
The kids in the hospital start to get better. Everyone is so relieved, they don't even wonder what happened to Dr. Heidecker. Michael lies to his mom that nothing special happened while she was at the hospital with his brother. Sam apologizes to Dean now his slavish devotion to following their dad's orders makes sense. But Sam feels sorry for Michael now he knows that nightmares are real, and he'll never be the same. Sam wishes he ever had that kind of innocence. Dean says he wishes Sam could, too.