Andre Norton - Dragon Magic [Kindle azw3]

A Hidden Treasure

Sig, Artie, Kim, and Ras live in the same neighborhood and go to the same school, but they have nothing in common...until each of them sneaks into the old abandoned house on the corner and discovers the strange puzzle box covered with pictures of four dragons. Drawn by powerful magic, the boys find themselves bound together by a mystery that will transform them all--and transport them into worlds that are populated by heroes and dragons of lore....