Mandy is always making new friends at the Animal Ark, her parents' famous veterinary practice. They are planning a special event in Welford for Christmas, during which they plan to raise money for little Alex, who is seriously ill, so that she can fly to America for an operation. Alex has a kitten, Sunshine, who she loves more than anything else in the world. Then one day, when Sunshine mysteriously disappears and is left somewhere outside in the snow, it almost breaks Alex's heart. Will Mandy and James find the kitten in time?