Most information about her World War II activities comes from her autobiography, Miss U. Utinsky was born in St. Louis, Missouri and grew up on a wheat farm in Canada.

On a sojourn to the Philippines in the late 1920s, she met and fell in love with John "Jack" Utinsky, a former Army captain who worked as a civil engineer for the U.S. government.

As the likelihood of a Japanese attack grew in the Far East, the U.S. military ordered all American wives back to the United States.

Unwilling to part from her husband, Utinsky refused to obey the order and took an apartment in Manila while Jack went to work in Bataan.

"[4] Aided by the Army and Navy commissaries and by a Chinese man called Lee, Utinsky hid in an apartment for ten weeks.

Upon hearing the news of the fall of Corregidor, she ventured out to search for her husband directly, seeking help from the priests of Malate Convent.

Through various contacts, she obtained false papers, creating the identity of Rena Utinsky, a Lithuanian nurse—as Lithuania was a nonbelligerent country under armed occupation by Nazi Germany.

[10] In August 1942, Flores and Utinsky visited Dr. R. Y. Atienza of the Philippine Red Cross near Cabanatuan and he agreed to assist by smuggling food and medicine into the camp.

A number of other people assisted Flores and Utinsky, including Catholic priests, Filipinos, an American, Claire Phillips, and a Spaniard who became the leader of the group, Ramon Amusategui.

Amusategui was executed in October 1944, but Flores escaped, taking refuge with the Hukbalahap guerrillas in the mountains for the remainder of the war.

[11] The activities of the Miss U Spy Ring may have also led to the execution in December 1944 of four American civilians resident in the Santo Tomas Internment Camp in Manila.

Prominent internee leaders A. F. Duggleby and Carroll Cawkins Grinnell and two apparently innocent men were executed in December 1944 for suspicion of aiding the POWs and anti-Japanese guerrillas.

According to one account, Catholic priests Lalor and Patrick Kelly, also helpful to Flores and Utinsky, were killed by the Japanese during the Battle of Manila in February 1945.