As Beth prepares for her school's upcoming Spring Carnival, eerie things seem to happen. First, an unknown vandal writes "THE CARNIVAL IS DOOMED" on the class chalkboard, and later, the art room is left completely trashed. It seems as if someone is trying to ruin the carnival, and the main culprit is Anthony Gonzales, the school's resident prankster. However, he denies the accusations and even seems frightened himself. Their teacher, Miss Gold, is also starting to act suspicious, all because of a mysterious black ring she's acquired, one that almost looks as if a face is moving inside, and one that according to Miss Gold, she can't seem to get off.
As the incidents at school continue, Beth grows paranoid that someone is out to hurt her and her classmates. Things get so bad that Miss Gold attempts to get the carnival canceled, but the principal declines. When the carnival does arrive, things seem to be going smoothly, until a mysterious, cloaked figure enters the school premises. The figure begins to cause mayhem in the gym, making the room spin, and the lights turn on and off. As the terror ensues, the police eventually arrive, tackling the stranger, and revealing Miss Gold to be the person behind the hood. Immediately, she begins shrieking that she didn't do it, but she is arrested anyway. As she is, though, she leaves behind her black ring for Beth to find. Before she knows what she's doing, Beth puts the black ring on her finger and feels it tighten until its completely stuck.
Following this, Beth begins to have strange nightmares. Hoping she can tell her how to take it off, Beth visits Miss Gold in the hospital. However, upon seeing the ring, Miss Gold breaks into a panic, telling Beth that she needs to get rid of it. Slowly, the ring begins to control Beth, like it did Miss Gold. She begins to act maliciously, pulling cruel pranks on her classmates, and even destroying her sister's doll collection. As she attempts to remove the ring, the entity within tells Beth that the evil is only beginning. Its words prove true, as Beth's actions grow more and more cruel as the ring's power over her continues.
When Beth partakes in a charity bike-a-thon, the ring tries to get Beth to cause a horrible accident for the other bikers. However, she fights the entity's urges and bikes back home. She uses a pair of metal cutters to remove the ring, but in the process, she sets free the evil spirit within. As it tries to possess her, Beth is able to transfer the ring from her finger to the body of Chirpy, a bird that she had rescued earlier in the book. With the evil now destroyed, Beth buries the bird so that nobody can ever find the ring again. However, it is revealed that her sister, Amanda, has bought an identical black ring, one that also seems to have a face inside.
Beth is a kind-hearted person, though she is often mocked and labeled a "goody-goody". She describes herself as an animal lover, which is why she rescues Chirpy at the beginning of the book. She has a crush on her classmate, Danny Jacobs, another thing her sister, Amanda, teases her over. When Beth puts on the black ring, she goes from kind to evil, vandalizing Anthony Gonzales' bike and sunglasses, and her sister's doll collection. However, she is strong enough to fight off the evil of the ring and is resourceful when defeating the entity within.
Beth describes herself as having red hair down to her shoulders, blue eyes, and a round face covered in freckles.