The Chronicles Of Narnia: Prince Caspian (Wii)
This game is titled The Chronicles Of Narnia: Prince Caspian in North America, Europe, and Australia, and Narnia Kuni Monogatari Dai-2-Shou: Caspian Ouji no Tsunobue in Japan.
When you see treasure keys on the ground, pick them up. They can be used to open treasure chests with a snowman floating above it.
Strategy guides from GameFAQs