Ring Of Fire Century Series, Book 1.

Every hundred years, four kids from four cities must save the world .Rome, December 29.A mix-up with their reservations forces Harvey from New York, Mistral from Paris, and Sheng from Shanghai to share a room with the hotel owner's daughter, Elettra. The four kids discover an amazing coincidence-they all have birthdays on February 29, Leap Day. That night, a strange man gives them a briefcase and asks them to take care of it until he returns. Soo...