Caroline in 1936 World War 2

Caroline is in America, 1936 during World War 2.
She overheard people say how creepy and poor World War 1 was.
20 million deaths!
So when SUB came to her house, she was tense. One day, mothers' friends arrived and asked Caroline and Ryan to join the military factory. But, trouble arrived once they went, with Aunt Jen's invitation. Ships were getting holes and guns had missing pieces. The ruiner didn't take the pieces because the ruiner wanted them to make it and then ruin it to waste their time and then run out of time to make new gadgets. Everyone at the factory agreed there was a spy.
With each day, Caroline got more and more suspicious. Can she find out who's the spy? Mother's friend, or a spy from the other side (Germany)?