Penelope Jane Parker - better known as PJ - is a precocious, sociable nine-year-old who, in the spring of her Grade 4 year, is keen to show her abilities as a sprinter in the annual school track meet. Her best friend, Katie, has no interest in competing in the footrace that PJ knows she, PJ, will win. What do best friends do? Well, PJ decides that, in order to encourage Katie, she'll slow down to give Katie a chance when they race together in the warm-ups the week before the meet, so her friend will feel better about herself. But, as the race begins and PJ slows down, suddenly Katie surges into the lead, and PJ is left huffing to catch up; in fact, Katie wins the race.
This begins a spiral of jealousy and anger and worry that causes a rupture in the friendship and a sequence of events during which PJ goes nuts trying to figure out how to retrieve her position as winner and good friend. PJ shops for a new best friend to no avail. Her parents strongly advise her to make up with Katie. Her brother mocks her. PJ's nine-year-old world is falling apart - and it's only after a number of disastrous stumbles that the friendship is repaired and equilibrium is restored. The story is told with a lot of humour - it's the lighter side of what can sometimes be the very nasty and destructive world of plot and counter-plot that can infest the social lives of girls.