We demonstrate that a single merger could explain first-order (intensity and size), morphological and kinematical properties of the disk, thick disk, bulge and streams in the halo of M31, as well as the observed distribution of stellar ages, and perhaps metallicities. It challenges the current scenarios assuming that each feature in the disk (the 10 kpc ring) or in its outskirts (thick disk, the Giant Stream and the numerous streams) are associated to an equivalent number of minor mergers. Here we focus on the substructures within the M31 halo including the Giant Stream, which ultimately may set up a more precise geometry of the encounter. We also tentatively show that the observations of the halo kinematics and chemistry can be predicted by our modeling without any further adjustment of the parameters.