An overweight, young teenager whose mother is having a nervous breakdown, and whose father doesn't know what to do, is invited to spend the summer with her cousin in Mississippi. Through telling lies about her background, she works her way into popularity on her cousin's coattails. Then a boyfriend tells her she should lose weight, and she pretends there is something wrong with her thyroid. Still, she jumps at the challenge of swimming across the lake (five miles) with him, which she accomplishes to great applause, but when she gets back, her parents are there to take her home. Back in Indiana, she tries to keep the glow of the summer dream.