Wringer is about peer pressure. Palmer LaRue dreads his upcoming tenth birthday. In his town, Family Fest is a yearly fundraiser that ends with an annual pigeon shoot, when entrants gun down five thousand live pigeons. Ten-year-old boys are "wringers." It is their task to break the necks of wounded pigeons. Palmer is horrified by the event but convinces himself for several years that the pigeons are better off. He and his friend, Dorothy Gruzik, avoid the pigeon shoot, sometimes playing on the swings well away from the shooting field and other times staying away from the park on that day. But as Palmer's tenth birthday approaches he wants to join a gang led by Beans, whose whole purpose in life, since age four, has been to become a wringer.
Palmer gains acceptance in the gang and is nicknamed "Snots." He learns to join their harassment of his one-time friend, Dorothy. All this does not lessen his dread of his tenth birthday. Then like the Ancient Mariner's albatross, a pigeon pecks on Palmer's bedroom window. He tries to scare it away without success, and when he opens the window, "Nipper" steps into Palmer's room, and Palmer becomes its protector.
To make matters worse, the gang discovers Palmer is hiding a pigeon. Palmer must invent ways to divert their attention, and the stress of concealing Nipper from his parents and from Beans nearly overwhelms him. Finally, Palmer apologizes to Dorothy and confides in her. She takes Nipper with her on a family outing to the beach to release him and ensure his safety, but unknowingly releases him where pigeons are captured for the pigeon shoot.
The stage is set for high drama. Palmer turns ten. The day of the pigeon shoot arrives. Palmer refuses to attend, but against his will, some unseen force pulls him to the shooting field. Palmer watches in fascinated horror as birds are released and killed or wounded. He is unable to turn away as ten-year-old boys race onto the field and break the necks of wounded birds. Dorothy comes to stand with Palmer and tells him she released Nipper in the city at the railroad yards instead of at the ocean. Alarmed by her revelation, Palmer knows the people-trusting Nipper is in one of the crates of pigeons waiting to be released. Palmer frantically searches the silent crates for Nipper. The birds all look alike. After what seems like hours, a bird steps out of the crate rather than flying. The shooter misses, and the bird flies up, but instead of flying on to freedom it circles and starts down. It's Nipper. How can Palmer save his friend?