An investigation of the unsteady hydromagnetic natural convection flow with heat and mass transfer of a viscous, incompressible, electrically conducting and heat absorbing fluid past an impulsively moving vertical plate with ramped temperature embedded in a fluid-saturated porous medium is carried out taking induced magnetic field and nth order chemical reaction into account. Governing equations along with the initial and boundary conditions are solved numerically using the Crank-Nicolson implicit finite difference scheme. The numerical solutions for fluid velocity, induced magnetic field, species concentration and fluid temperature are depicted graphically, whereas the numerical values of skin friction, Sherwood number and Nusselt number are presented in tabular form for various values of the pertinent flow parameters. In order to highlight the influence of ramped temperature distribution within the plate on the flow-field, the fluid flow past a ramped temperature plate is compared with the one past an isothermal plate. Validation of numerical results is also performed to ensure correctness of the results.