Signed with an X is about a Jewish baby, born in England, into a world on the verge of all-out war. Elsie, the young mother, describes her feelings as she listens to the BBC. Joe, the father, describes seeing Germany preparing for war, while England dithers between appeasement and denial.
The Jewish community in England is aware of what their fate would be should England fall to the Nazis. The likelihood of invasion seems obvious to most, especially to the Jews. While on holiday on the coast of England, Elsie thinks she hears guns firing. The next day, she reads in the Daily Express that she is right. The phone rings. England is at war. The family's lives are launched into survival mode.
The British government encourages parents who are able, to get their children out of London. The British government also stipulates that no money may be taken out of England. Arrangements are made for mother and daughter to take refuge in America. Jan, her mother, her mother's friend, and three other children are to cross the Atlantic aboard an English passenger ship. They are to cross the Atlantic on enemy seas on a British ship carrying a crew, women, and children, with a few reporters on board. WWII is revving up. The ship is unarmed, with no escort; it is defenseless.
Three years later, as the war descends into chaos, they return home, this time through a hurricane through enemy waters on a Portuguese ship, again, weaponless, unescorted, defenseless, full of women and children.
Elsie describes her "war" in her own words. Joe, Jan's father, who stays in London throughout the war, shares in his own words, and Jan, as she remembers, takes the reader on the bucking bronco we call "life."