The Summer the Spies Moved in — Mary Locke

FROM RUSSIA, WITH TROUBLE!
Meg knows a spy when she sees one. And Irina, the daughter of the Russian diplomat who has just moved into the house across the street, is definitely a spy.

Irina is also stubborn, opinionated, and unlike anyone Meg has ever met.

But Meg will do anything to catch a spy -- even if it means acting like Irina's best friend!