The Calder game

After 7th-grade friends Calder, Petra and Tommy go on a field trip to view Alexander Calder mobiles at a Chicago art museum, Calder accompanies his father on a business trip to a small village in England. A few days later, Calder and a donated Calder sculpture "The Minotaur" both disappear at the same time. Calder's father asks Petra and Tommy to fly to England to help find their friend.