We report the first observation of a reflecting longitudinal wave propagating through a hot coronal loop seen with the high temperature filter Be-thin of XRT, on board HINODE. The long coronal loop on the north-east limb shows the wave propagating from one foot-point to another and then gets reflected from the other foot-point. We also notice the wave getting damped heavily after one reflection. Using processed images we calculate the length of the loop and the speed of the wave propagation. The propagation speed indicates that it is a slow magneto-acoustic wave in nature. We also observe the same event in a high temperature AIA/SDO 94 Angstrom channel. Apart from measuring the wave speed and the loop length, we also estimate the loop density and the temperature by using automated 'Differential Emission Measure' (DEM) from the AIA data.