Spike It! — Matt Christopher

Jane is looking forward to the start of the volleyball season when her widower father drops a bombshell: he is planning to marry a woman with a teenage daughter of her own! Jane's new mother and stepsister go out of their way to be nice and accommodating, so she eagerly tries to adjust to the new people in her life. But when her stepsister, Michaela, suddenly becomes a star on Jane's volleyball team, Jane finds her jealousy of this newcomer more than she can bear.