Previous efforts to generate new pacemaker cells resulted in heart muscle cells that could beat on their own. Still, the modified cells were closer to ordinary muscle cells than to pacemaker cells. Other approaches employed embryonic stem cells to derive pacemaker cells. But, the risk of contaminating cancerous cells is a persistent hurdle to realizing a therapeutic potential with the embryonic stem cell-based approach. The new work, with astonishing simplicity, creates pacemaker cells that closely resemble the native ones free from the risk of cancer.