Living cells make fate-determining decisions based on signals from their environment. Understanding the decision making process is essential for unveiling the mysteries of life and for improving human health. I will discuss our recent study of a paradigmatic system of cell-fate determination, the bacterium E. coli and its virus – phage lambda, using live-cell imaging at the single virus resolution. Upon infection by phage lambda, E. coli undergoes one of two alternate pathways: lytic (violent) or lysogenic (dormant). Our study suggests a novel scenario in which the choice between lysis and lysogeny is first made at the level of individual viruses. The decisions by all viruses infecting a single cell are then integrated in a precise (noise-free) manner, such that only a unanimous vote by all viruses leads to the establishment of lysogeny. In the talk, I will also discuss how the measurement at high resolution (sub-cellular level) helps deepen our understanding of the decision making mechanism. ------------ Lanying Zeng is a postdoctoral researcher in the Department of Physics at the University of Illinois at Urbana-Champaign