A treasure map. A submarine. A secret legacy.

Zac and Steve are seven now, with their very own headquarters in the basement. But when Turbo the puppy runs over a creaky floorboard, the boys discover something amazing hidden underneath: a mysterious hand-drawn treasure map!

So begins their biggest adventure yet. A trail of clues leads the Kirsten-Carter Alliance all across Edinburgh, and to a family secret that's been waiting for them for years.

Zac (Mission Control) brings the brains and the gadgets.
Steve (The Interceptor) brings the speed and the courage.
And little Olivia (Agent Livi) brings her trusty pink flashlight, which turns out to be more important than anyone expected!

On this mission, the team will:

•Find a secret map hidden under the floorboards
•Build a homemade submarine, the Z-Diver, to explore a deep, dark pond
•Climb a mysterious chimney to follow the "sound of the wind"
•Sneak a tiny spy-cam into Edinburgh Castle (watch out for the castle cat!)
•Crack a star-chart code with a giant telescope
•Brave the spinning gears of an old clocktower
•Uncover the Sky-Shifter, an amazing flying submarine
•Race through the clouds and dive deep beneath the sea
•Face their rival Leo in a showdown at the zoo, with the whole city's power at stake

Packed with gadgets, clues, laughs and brilliant teamwork, The Tech-Lock Takedown is the most exciting Zac & Steve adventure so far!

Beautifully illustrated in full colour, with a picture opening every chapter.

Ready, Agents? The legacy is waiting!