Mikaela Kadono is bummed when her parents move the family into a spooky old fixer-upper house. When she finds the house contains a secret - a message from the distant past hidden in riddles and codes, she and her friends set off on a quest to solve the mystery. Their perilous adventure takes them from the high seas to a secret labyrinth of tunnels. Success, even survival, will take all their skills, gadgets, technology, and courage. As they unravel the mystery, it seems as if the message was left specifically for them. But how could the sender of the message have known about them 100 years ago? Are they being sent on this mission from someone in the past? Or someone in the future? Little do they know, they've become wrapped in an evil plot to take over the world that spans not only the last century, but those yet to come.