It's been just two weeks since Andrew and Evie received the first message from their missing mother. Two weeks since they discovered the truth about her disappearance. And now the twins are living in a new city, going to a new school - and they have another mysterious package from Spy X. Each item in the package is part of a pair, and it's up to the twins to find its match and pass it on to the right person. But Andrew and Evie have no idea who that person is. Nobody around them is what they seem - not their neighbors, not their teachers, not even kids at school. But the twins have to figure out who to trust - fast. Because Spy X is in trouble, and time is running out...