Icefall, by Matthew J. Kirby
This is a great mystery to read on a hot summer day. It takes place in a hidden fortress tucked between towering snow-covered mountains, a glacier, and a frozen fjord. The king's children, Solveig, Asa, and Harald, have been brought there for their safety until the king's battle is won. But soon it is discovered that there is a traitor in their midst. This gripping story will draw you deep into the icy world of the ancient Vikings and their myths.
Icefall is the 2012 winner of the Edgar Award for Best Juvenile Mystery. You can find lots more great mysteries by looking at the lists of winners and nominees awarded by the Mystery Writers of America.
What's your favorite mystery?