We identify the nucleation pathway for a liquid droplet of a water- like system. In order to calculate the free energy barrier associated with the droplet formation, we use the recently developed mu VT- S simulation method to unravel the nucleation process. We analyze the interdependence between droplet size, entropy and free energy of nucleation. Three key features emerge: the droplet size increases as entropy decreases during the process, the nucleation free energy increases as supersaturation decreases, and the nucleation free energy increases as T decreases. This method can be readily applied to calculate free energy barriers of activated events with entropy as the reaction coordinate. (C) 2018 Elsevier B. V. All rights reserved.