"When best friends Abbi and Skylar witness a clandestine meeting between a mysterious woman and someone in a dark van, they're thrilled. Finally, a mystery to spice up the summer! Who could these people be? Why are they meeting? Are they spies? Criminals? The two girls are determined to find out. But then a local woman goes missing and is found dead in the woods. And Abbi and Skylar realize that their detective work could hold the keys to solving...

"After taking down a mole within their organization, the City Spies are ready for their next mission--once again using their unique skills and ability to infiltrate places adults can't. The sinister Umbra has their sights set on recruiting a North Korean nuclear physicist by any means necessary, and the City Spies plan to keep an eye on his son by sending Paris to the chess prodigy's tournaments in Moscow and Beijing. Meanwhile, Sydney's embedded...