Reveals how two decidedly ordinary Englishwomen and sisters, Ida and Louise Cook, decided, after hearing an aria from Madame Butterfly, to save their earnings and go "undercover" as eccentric opera fans to rescue dozens of people from the Nazis.

"Europe, 1937. Two British sisters, one a dowdy typist, the other a soon-to-be famous romance novelist. One shared passion for opera. With prospects for marriage and families of their own cut down by the scythe of World War I, the Cook sisters have thrown themselves into their love of music, with frequent pilgrimages to Germany and Austria to see their favorite opera stars perform. But now with war clouds gathering and harassment increasing, the stars...