Mackenzie Ziegler has live in her older sister, Maddie's, shadow for a long time. Her mother, her dance teacher, and everyone always praise Maddie but never really pay any attention to Kenz...until one day. One day, Mackenzie was complaining about a bad headache and so her miter took her to the doctor. Turns out Kenzie has cancer. Will this be we last chance to dance? Will she finally be able to Shine?