This is going to take some setup, so just roll with it.
The players are looking for one of their sisters. They have found a supernatural being called the Face Merchant who has a doll shop in an otherspace (pocket dimension). The face merchant swapped the sister's identity with a dolls identity, as the Face Merchant doesn't see a difference between people and dolls. The PC's needed info to find the sister, and the Face Merchant agreed to provide that info if they retrieved some dolls from a client.
The client was an old daft woman named Judith who lived in a retirement home. She had dolls of her daughter Karen and her son-in-law David. She would talk to the dolls instead of her real children. She hated that Karen had married David because she is a miserable racist. She kept calling David a Mexican landscaper, when he is actually a Native-American dentist. She also routinely threw David doll in the garbage and generally abused it.
The PC's went to meet the actual David and Karen, and found they were lethargic and that David often fell and hurt himself. They figured out there was some sort of voodoo doll stuff going on here and that the lethargy was from the fact that the dolls at the old folks home were somehow stealing the vigor from the actual people, and that the abuse of the David doll was harming the real David.
The PC's decided to steal the dolls and, in order to protect the real world people from the effects, cast a ritual to protect the real Karen and David.
< That PC doesn't actually know how to do rituals. He, Davey, has a German shepherd named Goliath who talks to him in a clipped German accent and tells him how to do things.>
The next day when they went to get the dolls, a PC found Judith dead. She had been strangled and someone had drug her corpse under the bed. That PC heard something small moving through the air vents and, with a mirror, was able to see the dolls escaping.
<Davey asked Goliath if his ritual was responsible for Judith's death, and Goliath responded, "I vass chuss followink orders.">
He tried to stop them, but they escaped. Davey, the sheriff of the town, visited real David and Karen, and found they were now chipper and healthy. He sent them to the hospital to claim the mother's body, and got permission to search their house for clues.
While in their house, he heard something moving in the kitchen. He saw the cabinet door under the sink close, and heard something moving around. He duct-taped the doors closed to prevent escape and called the rest of the PCs.
When the rest of the PCs arrived, the sheriff tried to talk to the dolls through the door. He heard movement that finally stopped with the sound of something falling against the door. When they opened the door, the Karen doll fell out, motionless, holding the cap to a bleach bottle like a cup.
<Player interjection, "Oh, right, this is a horror game.">
When the sheriff looked further under the sink, he found that the David doll had hung himself.
They collected the dolls and returned them to the Face Merchant, who wept like her own children had died.
Unknown Armies is weird, yo.