The movie shows the simulated evolution of the vapor cloud of molecular hydrogen from the impact of LCROSS into the southern polar region of the Moon. The movie is displayed in the frame of reference of the LAMP instrument, with its field of view shown by the vertical red line at [0,0]. The LCROSS impact site moves to the left as time goes on in this reference frame. It shows how the timing of the signal LAMP detects is a combination of the expansion of the cloud and the motion of LRO past the impact site. It also shows how the signal observed by LAMP is from only a small portion of the entire cloud, emphasizing the need to use modeling to relate the observations to the overall release.