Uncovering the mystery behind Katherine Pierce is a real workout.

The Unicorns have won a month-long membership at the hottest health club in town! The club is renowned for its diet-and-exercise program, led by spokesmodel Katherine Pierce. Katherine is gorgeous, graceful, and adored by teenagers across the country. Jessica, Lila, Mandy, and Rachel are looking forward to getting in shape and meeting the famous Katherine. But if Katherine's so lucky, why does she look so miserable?