Five children, One world

When Hayley arrives at her grandparents house in London for vacation, she meets four very special children. Eugene, Wangera, Ling and Jack. They are all from different countries. Since they all want to learn about the different places, they decide to use their imagination and travel to the other countries. Every day, somebody else is the guide. Their friendship grows stronger and stronger. Will they ever be able to let Hayley go back to Australia when her vacation is over?