When she was young, Katalin Karik d̤ecided she would study science--even though she had never even met a scientist! But she was determined to learn as much as she could about the human body, and once she made a decision, she stuck with it. Katalin had to learn English while attending university, but she worked hard until she became a doctor. After facing many challenges, including lack of research funding and harsh immigration policies, Kati and her family uprooted from Hungary and moved to America, where she became a top researcher. She knew that, with work, she could teach one of the building blocks of life, messenger RNA, to fight off harmful viruses. There was just one problem--no one else believed Then, the COVID-19 pandemic hit, and Kati and her work were thrust into the spotlight. But with her unshakeable will, she was ready to face the challenge. Includes a note from Dr. Karikó, a time line, and more information about mRN