Proof Positive (Spy X, No. 3)

An exciting new spy series for kids ages 8-12 from master storyteller Peter Lerangis. Twins Andrew and Evie must decode clues that lead to their missing mother, a spy on the run from a gov't agency.

It's been almost a full year since Andrew and Evie's mom disappeared, and the twins are determined to find her. They've been following her trail, decoding the clues she's left them. And that trail is drawing them closer to their mother than ever before.
But now the Company is on to the fact that Mom is communicating with the twins -- and they'll do anything to get to her first. The Company's agents are desperate to intercept Mom's messages. It's up to Andrew and Evie to stop them -- and to find Mom before her enemies do.