[en] A Lagrangian density is constructed which is manifestly invariant under the orthosymplectic gauge group OSP(1;4) and under general co-ordinate transformations. This is done by the use of two multiplets, the symmetric and antisymmetric representations of OSP(1;4). The general features of OSP(m;2n) and in particular its irreducible representations are presented. The absence of OSP(1;4) symmetry from the ground state implements that one of the scalar fields, which is an element of the symmetric multiplet, has a non-vanishing vacuum expectation value. A shift on the fields reveals the physical spectrum of our Lagrangian. Two Goldstone fields are present, a vector and a spinor, corresponding to the breakdown of OSP(1;4) to the Lorentz group. The full Lagrangian contains a graviton, a massive spin-3/2 field and two massive scalar fields. The generalization to OSP(2;4) is immediate