Peter Cottontail is a young Easter Bunny who lives in April Valley, a lively hub where all Easter bunnies toil away crafting candy, sewing bonnets, and decorating and delivering Easter eggs to bring joy to families.
Colonel Wellington B. Bunny, the retiring Chief Easter Bunny, names Peter Cottontail as his successor, signaling a dream come true for the hopeful young rabbit who has long yearned to lead Easter. Meanwhile, a vengeful rabbit, January Q. Irontail, nourishes a grudge and plots to seize the title so he can ruin Easter for children, a punishment rooted in the old wound of a tail injury that left him with a prosthetic iron tail.
Irontail pushes for a constitutional contest to determine who delivers the most eggs, a rule-filled test meant to crown the best Easter emissary in April Valley. Peter accepts the challenge, but the night before the race, he overloads his social calendar and fails to rise on time. He tells his rooster to wake him at 5:30 a.m., yet Irontail sneaks in and feeds the rooster magic bubblegum, sealing the bird’s beak and keeping Peter asleep as the sun climbs high and crows cheer from the popping bubbles.
As the day unfolds, Irontail manages to deliver only a single egg, while Peter delivers none. With the scale tipped by this misstep, Irontail is anointed Chief Easter Bunny and wastes no time implementing a harsh new order: eggs painted brown and gray, candy sculpted into spiders and octopuses instead of bunnies and chicks, and galoshes worn in place of bonnets, all in a bid to sour the holiday for children.
Ashamed of his vanity and the chaos it caused, Peter leaves April Valley in search of a remedy. His journey leads him to Seymour S. Sassafras, an eccentric peddler and inventor who supplies the valley’s colors from a Garden of Surprises. Sassafras introduces Peter to the Yestermorrowbile, a time-traveling machine piloted by the French caterpillar Antoine, who will guide Peter back to Easter with a plan to deliver the eggs, win the contest, and defeat Irontail. Irontail catches wind of Peter’s plan and escalates his cheating by sending his spider to sabotage the Yestermorrowbile, threatening to send Peter and Antoine to any holiday but Easter.
Because the contest rules don’t explicitly require the eggs to land on Easter itself, Peter experiments with delivering the eggs on other holidays, hoping to outmaneuver the villain. On the 4th of July, he paints the eggs red, white, and blue and tries to fool two boys by disguising the eggs as firecrackers, a gambit that falls short. On Halloween, he encounters Madame Esmeralda, a witch, and offers her a Halloween egg as a gift, sparking a skirmish when Irontail dispatches Montresor, his bat, to steal the precious eggs. Peter recovers the eggs and yearns to return to Halloween to deliver them to Esmeralda’s friends, but Antoine cannot reverse the Yestermorrowbile and must land the craft to fix it.
Thanksgiving passes with no success, and the mission seems bogged down. On Christmas Eve, Peter, dressed as Santa, tries to distribute eggs on deserted streets, and he meets Bonnie, an Easter bonnet who has drifted away from April Valley years ago. Saddened that no one will buy her, Bonnie hears Peter’s offer to trade his Christmas eggs for her company. Yet Irontail steals them again, sending the chase into motion and forcing Peter to leave Antoine behind during the pursuit.
In a chaotic chase, Irontail and Montresor collide with Santa’s sleigh, and Santa returns the eggs to Peter. Grief overwhelms Peter, and he cannot even thank Santa properly as he watches Antoine remain behind. The longest stretch of regret follows, but the duo’s perseverance persists, and they finally land on a new holiday—Valentine’s Day. There, Peter encounters Donna, a friendly bunny, and offers her a Valentine egg, hoping this gesture might turn the tide. Yet Irontail again discovers the eggs and casts a spell that turns them all green, inside and out.
Presidents’ Day comes and goes with another setback, but Peter resolves to be honest and responsible. He and Bonnie arrive at St. Patrick’s Day with a renewed sense of purpose, and the second chance pays off. In the end, Peter succeeds in delivering the eggs and winning the contest, earning the title of Chief Easter Bunny. Antoine returns as a butterfly, and Irontail is relegated to the role of janitor in April Valley, while Peter leads a triumphant parade to celebrate Easter’s renewal.
