After thwarting a notorious villain at an eco-summit in Paris, the City Spies are gearing up for their next mission. Operating out of a base in Scotland, this secret team of young agents working for the British Secret Intelligence Service's MI6 division have honed their unique skills, such as sleight of hand, breaking and entering, observation, and explosives. All of these allow them to go places in the world of espionage where adults can't. Fourteen-year-old Sydney is a surfer and a rebel from Bondi Beach, Australia. She's also a field ops specialist for the City Spies. Sydney is excited to learn that she'll be going undercover on the marine research vessel the Sylvia Earle. But things don't go exactly as planned, and while Sydney does find herself in the spotlight, it's not in the way she was hoping. Meanwhile, there's been some new intel regarding a potential mole within the organization, offering the spies a lead that takes them to San Francisco, California. But as they investigate a spy who died at the Botanical Gardens, they discover that they are also being investigated. And soon, they're caught up in an exciting adventure filled with rogue missions and double agents!