They're not just a summer basketball squad--they're a lean, clean, adventure-finding team!

When The Lewis & Clark Squad discover a trunk full of old rifles--and one with a mysterious code written inside--they're off on their next adventure.

What does the code mean? And who could have put it there? The Squad wants to know.

Between basketball practices and games they follow up on all the clues. And those clues take them back more than 50 years to a robbery, an explosion, and the deeds of a mysterious stranger. There seems to be a link, but after almost a week of investigation, the kids still aren't sure what it is.

Then--a breakthrough! A girl with family connections to the rifle comes to town. If The Lewis & Clark Squad can catch up with her, they might be able to crack the code and put this mystery to rest. But then again, maybe the answer lies somewhere else . . .