Harriet and Holden Reynolds are third-grade twins who are as different as night and day! Harriet dreams of making a friend and winning the science fair, and Holden wants a prizewinning Holland Lop rabbit. Harriet's dreams come true when a new girl, Julie, moves to her school and they become science fair partners. Will their popcorn project take first place? Holden needs to earn fifty dollars to buy a purebred Holland Lop rabbit to show in the county fair, The only way Holden can earn the money is by walking the neighbor's yappy terriers, and when he finally finds a rabbit he can afford, it has faulty ears. Will his new rabbit, Hercules, be disqualified for not meeting breed standards? Harriet and Holden may be different, but one thing they have in common is their ability to get into a lot of misadventures!