Mary-Lou Trelawney returns to the Chalet School after a family tragedy, ready to take on new challenges as a Senior. But when a winter sledding accident leaves her seriously injured, Mary-Lou must draw on all her courage and determination to recover.

Meanwhile, jealous new student Jessica struggles to fit in, and troublemaker Emerence's reckless behavior puts others at risk. As Mary-Lou slowly heals, she helps Jessica overcome her resentment and Emerence face the consequences of her actions. With her irrepressible spirit and knack for bringing out the best in others, will Mary-Lou prove herself a true leader as she and her friends navigate the ups and downs of growing up at their beloved alpine school?