The face of the metal cube closest to the point charge, when brought near to it, had negative charge induced on it. This negative charge induces an equal and opposite positive charge on its immediate adjacent surface in the interior. In this way, the faces of the cube induce charges in the interior such that the total charge in the interior becomes zero. The net charge is on the surface of the cube, and it has a non-uniform charge distribution, consisting of both positive and negative charges.