After finally coming back from their long and eventful trip to Israel and Europe, the Rubinoff brothers and their friends, the Armon brothers, are ready for a vacation.
They decide to spend a peaceful vacation in the beautiful Thousand Islands region between Canada and the United States, but adventure and danger await them on Dark Island.
The Rubinoff and Armon brothers are drawn to the mysterious old castle on Dark Island like a magnet.
They discover the secret hideaway of an old Russian scientist and learn that they have discovered the key to an evil plot.
Can the boys stop the criminals before it's too late?